Information:  - The Council of Europe (CoE) is an international organisation focused on promoting human rights, democracy and the rule of law in Europe. Founded in 1949, it has 47 member states, covers approximately 820 million people and operates with an annual budget of approximately half a billion euros.   - Montegiardino is one of the 9 communes or "castelli" of San Marino. It has 910 inhabitants (October 2013) in an area of 3.31 km².   - Fiorentino is one of the 9 communes or "castelli" of the Republic of San Marino. It has 2,526 inhabitants (October 2013) in an area of 6.57 km².  - The Italian Peninsula or Apennine Peninsula ("Penisola appenninica") is the central and the smallest of the three large peninsulas of Southern Europe (between the Iberian Peninsula and the Balkan Peninsula). It extends from the Po Valley in the north to the central Mediterranean Sea in the south. The peninsula's shape gives it the nickname "lo Stivale" (the Boot). Three smaller peninsulas contribute to this characteristic shape, namely Calabria (the "toe"), Salento (the "heel") and Gargano (the "spur").  - Most Serene Republic ("Serenissima Respublica" in Latin) is a title attached to a number of European states through history. By custom, the appellation "Most Serene" is an indicator of sovereignty (see also Serene Highness or Most Serene Highness for a sovereign prince); consequently "Most Serene Republic" emphasizes the sovereignty of the republic.  - 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.  - San Marino, officially the Republic of San Marino, also known as the Most Serene Republic of San Marino, is an enclaved microstate surrounded by Italy, situated on the Italian Peninsula on the northeastern side of the Apennine Mountains. Its size is just over , with a population of 33,562. Its capital is the City of San Marino and its largest city is Dogana. San Marino has the smallest population of all the members of the Council of Europe.  - The City of San Marino ("Italian": Città di San Marino), also known simply as San Marino or locally as Città, is the capital city of the Republic of San Marino located on the Italian peninsula, near the Adriatic Sea. The city has a population of 4,128. It is on the western slopes of San Marino's highest point, Monte Titano.  - Monte San Cristoforo is a mountain of southern San Marino . It is located between the towns of Fiorentino and Montegiardino , and rises to a height of 534 metres .  - Dogana is a town and a civil parish ("curazia"), whose name means "Customs House"; it is located in the north-eastern corner of San Marino in the Serravalle municipality ("castello"). The town is the most populated settlement in the republic.  - The Apennines or Apennine Mountains (or ""a singular used in the plural) are a mountain range consisting of parallel smaller chains extending along the length of peninsular Italy. In the northwest they join with the Ligurian Alps at Altare. In the southwest they end at Reggio di Calabria, the coastal city at the tip of the peninsula. Since the year 2000 the Environment Ministry of Italy, following the recommendations of the Apennines Park of Europe Project, has been defining the Apennines System to include the mountains of north Sicily, for a total distance of . The system forms an arc enclosing the east side of the Ligurian and Tyrrhenian Seas.  - Italy, officially the Italian Republic, is a unitary parliamentary republic in Europe. Located in the heart of the Mediterranean Sea, Italy shares open land borders with France, Switzerland, Austria, Slovenia, San Marino and Vatican City. Italy covers an area of and has a largely temperate seasonal climate and Mediterranean climate; due to its shape, it is often referred to in Italy as "lo Stivale" (the Boot). With 61 million inhabitants, it is the fourth most populous EU member state.    Given the paragraphs above, decide what entity has the relation 'part of' with 'apennine mountains'.
A:
monte san cristoforo