Given the task definition, example input & output, solve the new input case.
In this task, you are given a context, a subject, a relation, and many options. Based on the context, from the options select the object entity that has the given relation with the subject. Answer with text (not indexes).
Example: Context: Joanne McLeod is a Canadian figure skating coach. She is the skating director at the Champs International Skating Centre of BC (formerly known as the BC Centre of Excellence). Here current and former students include Emanuel Sandhu, Mira Leung, Kevin Reynolds, Jeremy Ten, Nam Nguyen, and many others. In 2012, McLeod became the first level 5 certified figure skating coach in British Columbia., Victor Kraatz, MSC (born April 7, 1971) is a Canadian former ice dancer. In 2003, he and his partner, Shae-Lynn Bourne, became the first North American ice dancers to win a World Championship., Allie Hann-McCurdy (born May 23, 1987 in Nanaimo, British Columbia) is a Canadian ice dancer. McCurdy began skating at age eight and was a singles skater until age 12 when she switched to ice dancing. In 2003 she teamed up with Michael Coreno, with whom she was the 2010 Four Continents silver medalist and the 2008 Canadian bronze medalist. The pair retired in June 2010, to coach at the Gloucester Skating Club., Maikki Uotila - Kraatz ( born 25 February 1977 ) is a Finnish ice dancer . She is a former Finnish national champion with Toni Mattila . She married Victor Kraatz on June 19 , 2004 . The two coach in Vancouver , where they are the ice dancing directors at the BC Centre of Excellence . She and Kraatz have two sons , born September 14 , 2006 and July 10 , 2010 ., Burnaby is a city in British Columbia, Canada, located immediately to the east of Vancouver. It is the third-largest city in British Columbia by population, surpassed only by nearby Surrey and Vancouver., Canada (French: ) is a country in the northern half of North America. Its ten provinces and three territories extend from the Atlantic to the Pacific and northward into the Arctic Ocean, covering , making it the world's second-largest country by total area and the fourth-largest country by land area. Canada's border with the United States is the world's longest land border. The majority of the country has a cold or severely cold winter climate, but southerly areas are warm in summer. Canada is sparsely populated, the majority of its land territory being dominated by forest and tundra and the Rocky Mountains. About four-fifths of the country's population of 36 million people is urbanized and live near the southern border. Its capital is Ottawa, its largest city is Toronto; other major urban areas include Montreal, Vancouver, Calgary, Edmonton, Quebec City, Winnipeg and Hamilton., British Columbia (BC) is the westernmost province of Canada, with a population of more than four million people located between the Pacific Ocean and the Rocky Mountains.
British Columbia is also a component of the Pacific Northwest and the Cascadia bioregion, along with the U.S. states of Idaho, Oregon, Washington and Alaska., The "Champs International Skating Centre of British Columbia" (formerly known as the 'BC Centre of Excellence') is one of two major figure skating training centers in Canada. Located in Burnaby, British Columbia, it is home to many great national and international skaters. The programs there are overseen by a staff, including Joanne McLeod, who coaches 3-time Canadian men's national champion Emanuel Sandhu; Bruno Marcotte, who competed at the 2002 Winter Olympics; Victor Kraatz, the 2003 World Champion in ice dancing, and Maikki Uotila, who was a national champion in Finland. The center operates out of Canlan Ice Sports Burnaby 8 Rinks. Notable skaters who train there include Emanuel Sandhu, Mira Leung, Allie Hann-McCurdy & Michael Coreno, Jessica Millar & Ian Moram, Jeremy Ten, and Kevin Reynolds. This skating school is sometimes known as a training site for international competitors to practice for competitions in Vancouver. Champs International hosts its annual competition known as the BC/YK SummerSkate Competition every August., Shae-Lynn Bourne, MSC (born January 24, 1976) is a Canadian ice dancer. In 2003, she and partner Victor Kraatz became the first North American ice dancers to win a World Championship. They competed at three Winter Olympic Games, placing 10th at the 1994 Winter Olympics, 4th at the 1998 Winter Olympics, and 4th at the 2002 Winter Olympics., Vancouver, officially the City of Vancouver, is a coastal seaport city on the mainland of British Columbia, Canada, and the most populous city in the province., Subject: maikki uotila, Relation: country_of_citizenship, Options: (A) american (B) british (C) canada (D) finland (E) montreal
Output: finland
This is a good example, as maikki uotila is citizen of the finland.

New input case for you: Context: The Poltva River ( Ukrainian : ; Polish : Petew ) is a river in the western Ukrainian Oblast of Lviv and a tributary of the Bug River . The capital of the Lviv Oblast , Lviv , is located on the river . In the 19th century the river was included into the underground sewer system of Lviv ., The Second Polish Republic, also known as the Second Commonwealth of Poland or interwar Poland, refers to the country of Poland between the First and Second World Wars (19181939). Officially known as the Republic of Poland or the Commonwealth of Poland, the Polish state was recreated in 1918, in the aftermath of World War I. When, after several regional conflicts, the borders of the state were fixed in 1922, Poland's neighbours were Czechoslovakia, Germany, the Free City of Danzig, Lithuania, Latvia, Romania and the Soviet Union. It had access to the Baltic Sea via a short strip of coastline either side of the city of Gdynia. Between March and August 1939, Poland also shared a border with the then-Hungarian governorate of Subcarpathia. Despite internal and external pressures, it continued to exist until 1939, when Poland was invaded by Nazi Germany, the Soviet Union and the Slovak Republic, marking the beginning of World War II in Europe. The Second Republic was significantly different in territory to the current Polish state. It included substantially more territory in the east and less in the west., The Bug River (or Western Bug "Zakhidnyy Buh, ") is a major European river which flows through three countries with a total length of ., Lviv (', ', ; Yiddish: ; Latin: "Leopolis"), the largest city in western Ukraine and the seventh largest city in the country overall, is one of the main cultural centres of Ukraine. Named in honor of the Leo, the eldest son of Rus' King Daniel of Galicia. It was the capital of the Kingdom of GaliciaVolhynia (also called Kingdom of Rus') from 1272 to 1349, when it was conquered by King Casimir III the Great who then became known as the King of Poland and Rus'. From 1434, it was the regional capital of the Ruthenian Voivodeship in the Kingdom of Poland and was known as Lwow. In 1772, after the First partition of Poland, the city became the capital of the Habsburg Kingdom of Galicia and Lodomeria and was renamed to Lemberg. In 1918 in a short time was the capital of the West Ukrainian People's Republic. Between the wars, the city was known again as Lwow and was the centre of the Lwow Voivodeship in the Second Polish Republic. After World War II, it became part of the Soviet Union (Ukrainian SSR) and in 1991 of independent Ukraine.
Administratively, Lviv serves as the administrative center of Lviv Oblast and has the status of city of oblast significance. Its population is ., 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., Subject: poltva river, Relation: mouth_of_the_watercourse, Options: (A) main (B) sea (C) sea of azov (D) western bug
Output:
western bug