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: How many years did the owner of the private observatory live? Passage:It would seem that Gill's interests lay elsewhere since after a few years he sold the business, and then spent time equipping Lord Lindsay's private observatory at Dun Echt, Aberdeenshire. In 1874, Gill joined the expedition to Mauritius to observe the transit of Venus. Three years later he went to Ascension Island to observe a near approach of Mars and to calculate its distance. While carrying out these laborious calculations, he was notified of his appointment to the Cape Observatory, which, over the following 27 years he was to refurbish completely, turning it into a first-rate institution. Gill was a meticulous observer and had a flair for getting the best out of his instruments. His solar parallax observations with a heliometer and his calculations of distances to the nearer stars, are testimony to his outstanding work. He recruited Robert Innes to the Cape Observatory.
 Links: a. South African Astronomical Observatory b. Aberdeenshire (historic) c. James Lindsay, 26th Earl of Crawford d. South African Astronomical Observatory
Example Output: c

Example Input: Question: How old was the person who influenced Abani to join the revolutionary movement when they met? Passage:In 1914, Mukherji met Rash Behari Bose and joined the revolutionary movement. In 1915, he was sent to Japan to acquire weapons for the revolutionaries. According to British intelligence reports, he was active in the Hindu–German conspiracy. In September 1915, while on his return journey to India, he was arrested in Singapore and incarcerated at the Fort Canning prison there, where he remained until he escaped in the autumn of 1917. The exact details of his escape are unclear. Mukherji managed to reach Java in the Dutch East Indies, where he stayed until the end of 1919, living under the name of Dar Shaheer. In Java, he was in contact with Indonesian and Dutch revolutionaries and became a communist. He also travelled to Amsterdam and back. In Amsterdam, he met S.J. Rutgers, who recommended him as a delegate to the Second Congress of the Communist International.
 Links: a. Rash Behari Bose b. Singapore c. S. J. Rutgers d. Communism
Example Output: a

Example Input: Question: Was the institute that did not object when the Duetche Mark yielded established before or after the end of World War II? Passage:Montenegro has no currency of its own. As a constituent republic of the Socialist Federal Republic of Yugoslavia following World War II, and later of the Federal Republic of Yugoslavia, the Yugoslav dinar was the official currency in Montenegro. In November 1999, the government of Montenegro unilaterally designated the Deutsche Mark as its co-official currency with the dinar, and on 1 January 2001 the dinar officially ceased to be a legal tender in Montenegro. When the euro was introduced and the Deutsche Mark yielded, Montenegro followed suit and began using the euro as well, with no objection from the European Central Bank (ECB). The European Commission and the ECB have since voiced their discontent over Montenegro's unilateral use of the euro on several occasions.” A statement attached to their Stabilisation and Association Agreement with the EU read: "unilateral introduction of the euro was not compatible with the Treaty." The EU insists on the strict adherence to convergence criteria (such as spending at least 2 years in the ERMII system) which are not negotiable before euro adoption, but have not intervened to stop the unilateral adoption of the euro by Montenegro in 2002.
 Links: a. Stabilisation and Association Process b. Deutsche Mark c. European Central Bank d. Deutsche Mark
Example Output:
c