Context: The Amazon River (or ; Spanish and ) in South America is the largest river by discharge of water in the world, and according to some experts, the longest in length.
The headwaters of the Apurímac River on Nevado Mismi had been considered for nearly a century as the Amazons most distant source, until a 2014 study found it to be the Cordillera Rumi Cruz at the headwaters of the Mantaro River in Peru. The Mantaro and Apurímac confluence, and with other tributaries form the Ucayali River, which in turn confluences with the Marañón River upstream of Iquitos, Peru, to form what countries other than Brazil consider to be the main stem of the Amazon. Brazilians call this section the Solimões River above its confluence with the Rio Negro to form what Brazilians call the Amazon at the Meeting of Waters at Manaus, the river's largest city., Belém, literally Portuguese for Bethlehem, is a Brazilian municipality, the capital and largest city of the state of Pará in the country's north. It is the gateway to the River Amazon with a busy port, airport, and bus/coach station. Belém lies approximately 100 km upriver from the Atlantic Ocean, on the Pará River, which is part of the greater Amazon River system, separated from the larger part of the Amazon delta by "Ilha de Marajó" (Marajo Island). With an estimated population of 1,439,561 people  or 2,249,405, considering its metropolitan area  it is the 11th most populous city in Brazil, as well as the 16th by economic relevance. It is the second largest in the North Region, second only to Manaus, in the state of Amazonas., Roraima (Pemon: "roro imã", "parrot mountain" i.e. "Green Peak") is the northernmost and least populated state of Brazil, located in the Amazon region. It borders the states of Amazonas and Pará, as well as the nations of Venezuela and Guyana. The population is approximately 450,000 (2010) and the capital is Boa Vista. Roraima is the Brazilian state with the fewest municipalities, 15 in total., Chile, officially the Republic of Chile, is a South American country occupying a long, narrow strip of land between the Andes to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far south. Chilean territory includes the Pacific islands of Juan Fernández, Salas y Gómez, Desventuradas, and Easter Island in Oceania. Chile also claims about of Antarctica, although all claims are suspended under the Antarctic Treaty., Maranhão is a northeastern state of Brazil. To the north lies the Atlantic Ocean. Maranhão is neighboured by the (clockwise from east) states of Piauí, Tocantins and Pará. The people of Maranhão have a distinctive accent inside the common Northeastern Brazilian dialect. Maranhão is described in books such as "The Land of the Palm Trees" by Gonçalves Dias and "Casa de Pensão" by Aluísio Azevedo., The Atlantic Ocean is the second largest of the world's oceans with a total area of about . It covers approximately 20 percent of the Earth's surface and about 29 percent of its water surface area. It separates the "Old World" from the "New World"., The Anapu River is a river of Pará state in north - central Brazil ., Amapá is a state located in the northern region of Brazil. It is the second least populous state and the eighteenth largest by area. Located in the far northern part of the country, Amapá is bordered clockwise by French Guiana to the north, the Atlantic Ocean to the east, Pará to the south and west, and Suriname to the northwest. The capital and largest city is Macapá., Tin is a chemical element with the symbol Sn (for ) and atomic number 50, is a post-transition metal in group 14 of the periodic table. It is obtained chiefly from the mineral cassiterite, which contains tin dioxide, SnO. Tin shows a chemical similarity to both of its neighbors in group 14, germanium and lead, and has two main oxidation states, +2 and the slightly more stable +4. Tin is the 49th most abundant element and has, with 10 stable isotopes, the largest number of stable isotopes in the periodic table, thanks to its magic number of protons. It has two main allotropes: at room temperature, the stable allotrope is -tin, a silvery-white, malleable metal, but at low temperatures it transforms into the less dense grey -tin, which has the diamond cubic structure. Metallic tin is not easily oxidized in air., Guyana (pronounced or ), officially the Co-operative Republic of Guyana, is a sovereign state on the northern mainland of South America. It is, however, included in the Caribbean Region due to its strong cultural, historical, and political ties with the Caribbean Community (CARICOM). Guyana is bordered by the Atlantic Ocean to the north, Brazil to the south and southwest, Suriname to the east and Venezuela to the west. With , Guyana is the fourth-smallest country on mainland South America after Uruguay, Suriname and French Guiana., Ecuador, officially the Republic of Ecuador (which literally translates as "Republic of the Equator"), is a representative democratic republic in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean to the west. Ecuador also includes the Galápagos Islands in the Pacific, about west of the mainland., Brazil, officially the Federative Republic of Brazil, is the largest country in both South America and Latin America. As the world's fifth-largest country by both area and population, it is the largest country to have Portuguese as an official language and the only one in the Americas. Bounded by the Atlantic Ocean on the east, Brazil has a coastline of . It borders all other South American countries except Ecuador and Chile and covers 47.3% of the continent's land area. Its Amazon River basin includes a vast tropical forest, home to diverse wildlife, a variety of ecological systems, and extensive natural resources spanning numerous protected habitats. This unique environmental heritage makes Brazil one of 17 megadiverse countries, and is the subject of significant global interest and debate regarding deforestation and environmental protection., Pará is a state in northern Brazil traversed by the lower Amazon River. It borders the Brazilian states of (clockwise from north) Amapá, Maranhão, Tocantins, Mato Grosso, Amazonas and Roraima. To the northwest it also borders Guyana and Suriname, and to the northeast it borders the Atlantic Ocean. The capital and largest city is Belém, located at the mouth of the Amazon at the Atlantic Ocean and the 11th most populous city in the country., Subject: anapu river, Relation: mouth_of_the_watercourse, Options: (A) amazon (B) atlantic ocean (C) main (D) marañón river (E) pacific ocean (F) pará river (G) rio negro (H) ucayali river
Output: pará river