In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Example Input: Question: What was the founding date of the team Foster played against in the 2001 FA Trophy final? Passage:After a short period in Scotland, Foster returned to English football with Doncaster Rovers where his opportunities were limited, though he had a spell with Ilkeston Town on loan. In 2001, he signed for Forest Green Rovers in the Conference National. He made well over 100 appearances for the club and had a spell as captain. He also appeared for Forest Green in the 2001 FA Trophy final at Villa Park but was on the losing side in a 1-0 defeat to Canvey Island. He was highly regarded amongst the supporters at The Lawn and many were sad to see him leave when he departed for Halifax Town in 2004. He made just under 100 league appearances for Halifax at The Shay before a move in 2007 to Oxford United.
Links: a. Villa Park b. Canvey Island F.C. c. Halifax Town A.F.C. d. The Shay
Example Output: b

Example Input: Question: In which country is the seaport city of Porto located where the wine received its name "port"? Passage:Port is produced from grapes grown and processed in the demarcated Douro region. The wine produced is then fortified by the addition of a neutral grape spirit known as aguardente to stop the fermentation, leaving residual sugar in the wine, and to boost the alcohol content. The fortification spirit is sometimes referred to as brandy but it bears little resemblance to commercial brandies. The wine is then stored and aged, often in barrels stored in a Lodge (meaning "cellar") as is the case in Vila Nova de Gaia, before being bottled. The wine received its name, "port", in the later half of the 17th century from the seaport city of Porto at the mouth of the Douro River, where much of the product was brought to market or for export to other countries in Europe. The Douro valley where port wine is produced was defined and established as a protected region, and the name Douro thus an official appellation, in 1756, making it the third oldest, after Chianti (1716) and Tokaj (1730).
Links: a. Barrel b. Tokaji c. Vila Nova de Gaia d. Porto
Example Output: d

Example Input: Question: What is the full name for the enforcement body that arrested Ottwalt and his wife? Passage:In 1933, Ottwalt and his wife, Waltraut, left Germany and went into exile in Denmark, then, by way of Czechoslovakia, ended up in the Soviet Union. Living in Moscow, Ottwalt wrote for the German exile magazine Internationale Literatur (published by Johannes R. Becher) and was an editor at Vegaar Bibliothek. He also wrote for the Deutsche Zentral Zeitung. In 1936, he and his wife were ensnared in the Stalinist purges and arrested by the Soviet secret police, the NKVD. He was charged with suspicion of espionage, sentenced to forced labor and deported to a gulag near Archangelsk. His wife was sentenced to forced labor in Kotlas. She was deported back to Germany in January 1941 and didn't learn about his death until January 1958, when the Soviet Red Cross informed her that her husband had died on 24 August 1943.
Links: a. Deutsche Zentral-Zeitung b. NKVD c. Stalinism d. Gulag
Example Output:
b