Question: SS Cap Polonio's destination port was the leading transshipment point for foreign trade of which country in South America?

full_context: Document 1: Marco Polo (1851 ship): Marco Polo was a three-masted wooden clipper ship, launched in 1851 at Saint John, New Brunswick. She was named after Venetian traveler Marco Polo. The ship carried emigrants and passengers to Australia and was the first vessel to make the trip in under six months. Later in her career, the ship was used as a cargo ship before being run aground off Cavendish, Prince Edward Island in 1883.
Document 2: MV Monte Cervantes: SS "Monte Cervantes" was a 500 ft German passenger liner that cruised the South American route from Buenos Aires to Puerto Madryn (Chubut) to Punta Arenas to Ushuaia and return to Buenos Aires. The ship sailed under German registration and belonged to the South American Hamburg Company. After only two years of service she sank at the beginning of 1930 near Tierra del Fuego. The ship became known as "The "Titanic" of the South."
Document 3: Port of Buenos Aires: The Port of Buenos Aires (Spanish: "Puerto de Buenos Aires" ) is the principal maritime port in Argentina. Operated by the "Administración General de Puertos" (General Ports Administration), a state enterprise, it is the leading transshipment point for the foreign trade of Argentina.
Document 4: Argentine Naval Prefecture: The Argentine Naval Prefecture (Spanish: Prefectura Naval Argentina or PNA) is a service of the Argentine Security Ministry charged with protecting the country's rivers and maritime territory. It therefore fulfills the functions of other countries' coast guards, and furthermore acts as a gendarmerie force policing navigable rivers.
Document 5: RMS Homeric (1913): RMS "Homeric", originally launched as "Columbus", was built for Norddeutscher Lloyd and launched in 1913 at the F. Schichau yard in Danzig. "Columbus" was ceded to Great Britain in 1919 as part of German war reparations. She was sold to White Star Line in 1920, which named her "Homeric". Her sister ship "Hindenburg" retained her German ownership and was renamed "Columbus". "Homeric" was operated by White Star from 1922 to 1935.
Document 6: Law enforcement in Argentina: In Argentina the most important law enforcement organization is the Argentine Federal Police (equivalent to the FBI in the USA) with jurisdiction in all Argentine territory. Most routine police work is carried out by provincial police forces (equivalent to state police in the United States). An exception of the capital city of Buenos Aires (a federal district), where the Argentine Federal Police works with Argentine Naval Prefecture (Coast Guard) and Buenos Aires City Police (Municipal police).
Document 7: Mar del Plata: Mar del Plata is an Argentine city in the southeast part of Buenos Aires Province located on the coast of the Atlantic Ocean. It is the head of General Pueyrredón Partido. Mar del Plata is the second largest city in Buenos Aires Province. The name "Mar del Plata" has the meaning of "sea of the Silver region" or "adjoining sea to the (River) Silver region". Mar del Plata is one of the major fishing ports and the biggest seaside beach resort in Argentina.
Document 8: Imperator-class ocean liner: The "Imperator" class ocean liners were a series of three ocean liners designed for the Hamburg America Line, commonly known as "HAPAG". These three ships were commissioned by the chairman of HAPAG Albert Ballin. Namely the "Imperator" (1912), the "Vaterland" (1913) and the largest, the "Bismarck" (1914). These liners were over 50,000 tons, sported three funnels and had a length ranging from 906 ft (276 m) to 955.8 ft (291.3 m). To this day, the "Vaterland" is the largest passenger ship operated by a German shipping company.
Document 9: RMS Laconia (1921): The second RMS "Laconia" was a Cunard ocean liner, built by Swan, Hunter & Wigham Richardson as a successor of the 1911-1917 "Laconia". The new ship was launched on 9 April 1921, and made her maiden voyage on 25 May 1922 from Southampton to New York City. At the outbreak of World War II she was converted into an Armed Merchant Cruiser, and subsequently a troopship. Like her predecessor, sunk during the First World War, this "Laconia" was also destroyed by a German submarine. Some estimates of the death toll have suggested that over 1,649 people were killed when the "Laconia" sank. The U-boat commander Werner Hartenstein then staged a dramatic effort to rescue the passengers and the crew of "Laconia", which involved additional German U-boats and became known as the Laconia incident.
Document 10: SS El Capitan (1917): El Capitan, United States Official Number 285587, was built in 1917 by the Newport News Shipbuilding and Drydock Company at Newport News, Virginia for the Southern Pacific Company's Atlantic Steamship Lines. In 1915 the line operated from the North River piers 49—52 at the foot of 11th Street in New York to New Orleans under the flag and name of Morgan Line, which combined with the Southern Pacific's rail service from the Pacific Coast was known as the Sunset Gulf Route. During World War I the ship was purchased from the builder before delivery to the owner by the United States Shipping Board (USSB) which later turned the ship over to the United States Navy which placed her in commission as USS "El Capitan" (ID-1407) from 1918 to 1919. "El Capitan" was returned to commercial service by the Southern Pacific Company until just before the United States entry into World War II when the United States War Shipping Administration (WSA) acquired the ship, changed her registry to Panama and placed her in operation under its agent, United States Lines. "El Capitan" was in the Arctic convoy PQ-17 to the Soviet Union when she came under air attack on 9 July 1942, was damaged and abandoned to be sunk by torpedo just after midnight on 10 July.
Document 11: Puerto Madero: Puerto Madero, also known within the urban planning community as the Puerto Madero Waterfront, is a barrio (district) of the Argentine capital at Buenos Aires CBD, occupying a significant portion of the Río de la Plata riverbank and representing the latest architectural trends in the city of Buenos Aires.
Document 12: SS Cap Polonio: SS "Cap Polonio" was a German  GRT ocean liner that was launched in 1914 and scrapped in 1935. She worked the Hamburg Südamerikanische Dampfschifffahrtsgesellschaft ("Hamburg South America Steamship Company") route between Hamburg in Germany and Buenos Aires in Argentina. She was named after Cabo Polonio in Uruguay.
Document 13: Argentina: Argentina ( ; ] ), officially the Argentine Republic (Spanish: "República Argentina" ), is a federal republic in the southern portion of South America. Sharing the bulk of the Southern Cone with its neighbor Chile to the west, the country is also bordered by Bolivia and Paraguay to the north, Brazil to the northeast, Uruguay and the South Atlantic Ocean to the east, and the Drake Passage to the south. With a mainland area of 2780400 km2 , Argentina is the eighth-largest country in the world, the second largest in Latin America, and the largest Spanish-speaking one. The country is subdivided into twenty-three provinces (Spanish: "provincias" , singular "provincia") and one autonomous city ("ciudad autónoma"), Buenos Aires, which is the federal capital of the nation (Spanish: "Capital Federal" ) as decided by Congress.
Document 14: Buenos Aires: Buenos Aires ( or ; ] ) is the capital and most populous city of Argentina. The city is located on the western shore of the estuary of the Río de la Plata, on the South American continent's southeastern coast. "Buenos aires" can be translated as "fair winds" or "good airs", but the first one was the meaning intended by the founders in the 16th century, by the use of the original name "Real de Nuestra Señora Santa María del Buen Ayre". The Greater Buenos Aires conurbation, which also includes several Buenos Aires Province districts, constitutes the fourth-most populous metropolitan area in the Americas, with a population of around 17 million.
Document 15: RMS Caronia: RMS "Caronia" was a  gross register tons (GRT) passenger ship of the Cunard Line (then Cunard White Star Line). Launched on 30 October 1947, she served with Cunard until 1967. She was nicknamed the "Green Goddess". She is credited as one of the first "dual-purpose" built ships: suited to cruising, but also capable of transatlantic crossings. After leaving Cunard she briefly served as SS "Caribia" in 1969, after which she was laid up in New York until 1974 when she was sold for scrap. While being towed to Taiwan for scrapping, she was caught in a storm on 12 August. After her tow lines were cut, she repeatedly crashed on the rocky breakwater outside Apra Harbor, Guam and broke into three sections.
ground_truth: Argentina