Given the question: Information:  - Silesia (or  ; Silesian German: "Schläsing" Silesian: "lnsk" ) is a region of Central Europe located mostly in Poland, with small parts in the Czech Republic and Germany. Its area is about , and its population about 8,000,000. Silesia is located along the Oder river. It consists of Lower Silesia and Upper Silesia.  - Blansko is a town in Blansko District in the South Moravian Region of the Czech Republic. Blansko is the biggest town in Blansko District to which it lends its name. Blansko is situated in the valley of the river Svitava. The centre of Blansko is 276 metres above sea level, with the majority of the city situated on a slope above the left bank of the Svitava. Blansko currently occupies an area of and has approximately 20,800 inhabitants . The town is notable for the proximity of the Moravian Karst.  - The Svitava ( German : Zwittawa ) is a river in the Pardubice and South Moravian regions of the Czech Republic . The Svitava rises near Svitavy , passes through Blansko , and flows into the Svratka in the Moravian city of Brno .  - Brno (German: "Brünn") is the second largest city in the Czech Republic by population and area, the largest Moravian city, and the historical capital city of the Margraviate of Moravia. Brno is the administrative center of the South Moravian Region in which it forms a separate district (Brno-City District). The city lies at the confluence of the Svitava and Svratka rivers and has about 400,000 inhabitants; its greater metropolitan area is home to more than 800,000 people while its larger urban zone had a population of about 730,000 in 2004.  - The Moravian Karst is a karst landscape and protected nature reserve to the north of Brno in the eastern part of the Czech Republic, located near the town of Blansko. It encompasses a number of notable geological features, including roughly 1100 caverns and gorges and covers an area of roughly 92 km². Currently, five of the cave systems (Punkva Caves, Balcarka Cave, Kateinská Cave, Výpustek Cave and Sloupsko-šošvské Caves), Býí skála Cave (closed) and Stránská skála (out of the border) are open for public tours and exploration.  - The Czech Republic, also known by the short name Czechia, is a nation state in Central Europe bordered by Germany to the west, Austria to the south, Slovakia to the east and Poland to the northeast. The Czech Republic covers an area of with mostly temperate continental climate and oceanic climate. It is a unitary parliamentary republic, has 10.5 million inhabitants and the capital and largest city is Prague, with over 1.2 million residents. The Czech Republic includes the historical territories of Bohemia, Moravia, and Czech Silesia.    After reading the paragraphs above, we are interested in knowing the entity with which 'svitava ' exhibits the relationship of 'tributary'. Find the answer from the choices below.  Choices: - oder  - punkva  - svitava
The answer is:
punkva