Q:Information:  - The Sea of Azov ("Azovs'ke more/Azovke more") is a sea in Eastern Europe. To the south it is linked by the narrow (about ) Strait of Kerch to the Black Sea, and it is sometimes regarded as a northern extension of the Black Sea. The sea is bounded in the north by mainland Ukraine, in the east by Russia, and in the west by the Crimean Peninsula. The Don and Kuban are the major rivers that flow into it. The Sea of Azov is the shallowest sea in the world, with the depth varying between . There is a constant outflow of water from the Sea of Azov to the Black Sea.  - Podolia or Podilia (, , ) is a historic region in Eastern Europe, located in the west-central and south-western portions of present-day Ukraine and in northeastern Moldova (i.e. northern Transnistria). The term is derived from Old Slavic "po", meaning "by/next to/along", and "dol", "valley" (see dale).  - The Dniester River, or Dnister River ( translit. "Dnister", , ) is a river in Eastern Europe. It runs first through Ukraine and then through Moldova (from which it separates the breakaway territory of Transnistria), finally discharging into the Black Sea on Ukrainian territory again.  - Bulgaria (tr. '), officially the Republic of Bulgaria (tr. '), is a country in southeastern Europe. It is bordered by Romania to the north, Serbia and Macedonia to the west, Greece and Turkey to the south, and the Black Sea to the east. With a territory of , Bulgaria is Europe's 16th-largest country.  - The Southern Bug, also called Southern Buh ("Pivdennyi Buh" "Yuzhny Bug"), and sometimes Boh River, is a river located in Ukraine. It is the second longest river in Ukraine.  - Turkey, officially the Republic of Turkey (Turkish: ), is a transcontinental country in Eurasia, mainly in Anatolia in Western Asia, with a smaller portion on the Balkan peninsula in Southeast Europe. Turkey is a democratic, secular, unitary, parliamentary republic with a diverse cultural heritage. Turkey is bordered by eight countries: Greece to the west; Bulgaria to the northwest; Georgia to the northeast; Armenia, the Azerbaijani exclave of Nakhchivan and Iran to the east; and Iraq and Syria to the south. The Aegean Sea is to the west, the Black Sea to the north, and the Mediterranean Sea to the south. The Bosphorus, the Sea of Marmara, and the Dardanelles, which together form the Turkish Straits, divide Thrace and Anatolia; they also separate Europe and Asia. Turkey's location has given it geopolitical and strategic importance throughout history.  - Vinnytsia (, "Vinnytsia"; "Vinnitsa";  and ) is a city in west-central Ukraine, located on the banks of the Southern Bug.  - The Crimean Peninsula ("Krymskiy poluostrov;" , "Kryms'ky pivostriv"), also known simply as Crimea ( "Krym" "Krym"), is a major land mass on the northern coast of the Black Sea that is almost completely surrounded by both the Black Sea and the smaller Sea of Azov to the northeast. The peninsula is located south of the Ukrainian region of Kherson and west of the Russian region of Kuban. It is connected to Kherson Oblast by the Isthmus of Perekop and is separated from Kuban by the Strait of Kerch. The Arabat Spit is located to the northeast, a narrow strip of land that separates a system of lagoons named Sivash from the Sea of Azov.  - The Vovk River is river in Ukraine . If translated into English , the river name means wolf . It flows through Khmelnytskyi Oblast ( province ) of western Ukraine and is tributary of Southern Buh of Black Sea basin . Vovk flows through Derazhnya and enters Southern Buh in Letychiv .  - Letychiv  is a town in the eastern part of Khmelnytskyi Oblast (province) of western Ukraine. 51 km from Khmelnytskyi and 33 km from the railway station Derazhnya. Administrative center since Tsarist times, formerly in Podolia Province, although now it is administratively a part of the Letychiv Raion. Population: 11,081 inhabitants (2001 census). There are brickworks, dairy, plant of construction material in the town. Located 49°23'N, 27°37'E on the main road between Khmelnitsky and Vinnytsia at the confluence of the Volk and the Southern Bug rivers.  - Ukraine (tr. ) is a sovereign state in Eastern Europe, bordered by Russia to the east and northeast, Belarus to the northwest, Poland and Slovakia to the west, Hungary, Romania, and Moldova to the southwest, and the Black Sea and Sea of Azov to the south and southeast, respectively. Ukraine is currently in territorial dispute with Russia over the Crimean Peninsula which Russia annexed in 2014 but which Ukraine and most of the international community recognise as Ukrainian. Including Crimea, Ukraine has an area of , making it the largest country entirely within Europe and the 46th largest country in the world. It has a population of about 44.5 million, making it the 32nd most populous country in the world.  - An ocean (the sea of classical antiquity) is a body of saline water that composes much of a planet's hydrosphere. On Earth, an ocean is one of the major conventional divisions of the World Ocean, which covers almost 71% of its surface. These are, in descending order by area, the Pacific, Atlantic, Indian, Southern (Antarctic), and Arctic Oceans. The word "sea" is often used interchangeably with "ocean" in American English but, strictly speaking, a sea is a body of saline water (generally a division of the world ocean) partly or fully enclosed by land.  - Western Asia, West Asia, Southwestern Asia or Southwest Asia is the westernmost subregion of Asia. The concept is in limited use, as it significantly overlaps with the Middle East (or Near East), the main difference being the exclusion of Egypt (which would be counted as part of North Africa). The term is sometimes used for the purposes of grouping countries in statistics.  - The Black Sea is a body of water between Eastern Europe and Western Asia, bounded by Bulgaria, Georgia, Romania, Russia, Turkey, and Ukraine. It is supplied by a number of major rivers, such as the Danube, Dnieper, Rioni, Southern Bug, and Dniester. The Black Sea has an area of (not including the Sea of Azov), a maximum depth of , and a volume of . It is constrained by the Pontic Mountains to the south and by the Caucasus Mountains to the east, and features a wide shelf to the northwest. The longest east-west extent is about .  - Poland, officially the Republic of Poland, is a country in Central Europe, situated between the Baltic Sea in the north and two mountain ranges (the Sudetes and Carpathian Mountains) in the south. Bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine and Belarus to the east; and the Baltic Sea, Kaliningrad Oblast (a Russian exclave) and Lithuania to the north. The total area of Poland is , making it the 69th largest country in the world and the 9th largest in Europe. With a population of over 38.5 million people, Poland is the 34th most populous country in the world, the 8th most populous country in Europe and the sixth most populous member of the European Union. Poland is a unitary state divided into 16 administrative subdivisions, and its capital and largest city is Warsaw. Other metropolises include Kraków, Wrocaw, Pozna, Gdask and Szczecin.  - Europe is a continent that comprises the westernmost part of Eurasia. Europe is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, and the Mediterranean Sea to the south. To the east and southeast, Europe is generally considered as separated from Asia by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways of the Turkish Straits. Yet the non-oceanic borders of Europea concept dating back to classical antiquityare arbitrary. The primarily physiographic term "continent" as applied to Europe also incorporates cultural and political elements whose discontinuities are not always reflected by the continent's current overland boundaries.  - A sea is a large body of salt water that is surrounded in whole or in part by land. More broadly, "the sea" is the interconnected system of Earth's salty, oceanic watersconsidered as one global ocean or as several principal oceanic divisions. The sea moderates Earth's climate and has important roles in the water cycle, carbon cycle, and nitrogen cycle. Although the sea has been traveled and explored since prehistory, the modern scientific study of the seaoceanographydates broadly to the British "Challenger" expedition of the 1870s. The sea is conventionally divided into up to five large oceanic sectionsincluding the International Hydrographic Organization's four named oceans (the Atlantic, Pacific, Indian, and Arctic) and the Southern Ocean; smaller, second-order sections, such as the Mediterranean, are known as "seas".  - The Danube (, known by various names in other languages) is Europe's second-longest river, after the Volga River, and also the longest river in the European Union region. It is located in Central and Eastern Europe.  - Romania is a sovereign state located in Southeastern Europe. It borders the Black Sea, Bulgaria, Ukraine, Hungary, Serbia, and Moldova. It has an area of and a temperate-continental climate. With 19.94 million inhabitants, the country is the seventh-most-populous member state of the European Union. The capital and largest city, Bucharest, with its 1,883,425 inhabitants is the sixth-largest city in the EU.  - A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as stream, creek, brook, rivulet, and rill. There are no official definitions for the generic term river as applied to geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in some parts of the United States, "burn" in Scotland and northeast England, and "beck" in northern England. Sometimes a river is defined as being larger than a creek, but not always: the language is vague.  - The Caucasus Mountains are a mountain system in Eurasia between the Black Sea and the Caspian Sea in the Caucasus region.    After reading the paragraphs above, we are interested in knowing the entity with which 'vovk river' exhibits the relationship of 'mouth of the watercourse'. Find the answer from the choices below.  Choices: - arctic ocean  - atlantic ocean  - black sea  - caspian sea  - danube  - dniester  - kuban  - main  - po  - sea  - sea of azov  - southern bug  - ural river  - volga
A:
southern bug