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: Which team was ranked the highest at the 2009 Pacific Nations Cup? Passage:The 2009 Pacific Nations Cup is a rugby union tournament held between five national sides on the Pacific Rim: Fiji, Japan, Samoa, Tonga and the Junior All Blacks. The New Zealand Māori team that won the tournament last year will no longer take part in this competition because of a decision taken by the New Zealand Rugby Union. Australia A has also decided to pull out due to a similar decision. The inaugural competition was held in 2006. This year the tournament will begin on June 12 and ends on July 3, 2009 and most of the matches will be hosted by Fiji. The awarding of the key international tournament to the Fiji Rugby Union represents a further boost to the continued development of rugby in the region. The two opening round matches will be played outside of Fiji with Samoa hosting the Junior All Blacks in Apia and Tonga entertaining the Fijians in Nukuʻalofa the following day before the tournament moves to Fiji for a 17-day festival of international rugby spread across three match venues: the ANZ National Stadium (Suva), Churchill Park (Lautoka) and Lawaqa Park (Sigatoka).
 Links: a. New Zealand Rugby b. Fiji national rugby union team c. Samoa national rugby union team d. New Zealand Rugby
Example Output: b

Example Input: Question: How old was Beloff's husband when he died? Passage:Anne Beloff was born in 1921 in Hampstead to Simon Beloff and Marie Katzin. Her parents were of Russian–Jewish background, and her siblings included the historian Max Beloff, Baron Beloff, the psychologist John Beloff, the journalist Nora Beloff, and the politician Renee Soskin. She earned a degree in chemistry from University College London in 1942 before completing a PhD in the biochemistry of skin burns with Rudolph Peters at the University of Oxford. She visited Harvard Medical School in 1946 to perform research and returned to the UK in 1948. In the same year she married Ernst Boris Chain, a biochemist who had won the Nobel Prize in Physiology or Medicine in 1945, and moved with him to Rome.
 Links: a. Harvard Medical School b. Ernst Chain c. University of Oxford d. Hampstead
Example Output: b

Example Input: Question: How long had Charles V been Emperor of the Holy Roman Empire for the year he signed the Treaty of Speyer? Passage:The Treaty of Speyer or Peace of Speyer was signed on May 23, 1544 between Denmark-Norway and the Holy Roman Empire during an Imperial Diet of the Holy Roman Empire in Speyer, Germany. Danish-Norwegian king Christian III had imposed heavy tolls on the Sound and two other channels between the North Sea and the Baltic sea, in an effort to end the Dutch dominance of trade in the Baltic region. Under pressure from Holy Roman Emperor Charles V, he agreed to exempt the Dutch ships from these tolls and give them free and unfettered access to the Baltic. In the treaty, Charles V also recognized Christian III as the rightful king of Denmark and Norway, and promised not to provide military support to his rival Christian II. The Treaty of Speyer dictated Christian III's foreign policy for the rest of his life. He kept Denmark-Norway at peace, refusing to involve the countries in Protestant-Catholic conflicts such as the Schmalkaldic War of 1546. The Dutch would continue to dominate Baltic trade for another two centuries.
 Links: a. Charles V, Holy Roman Emperor b. Speyer c. Imperial Diet (Holy Roman Empire) d. Charles V, Holy Roman Emperor
Example Output:
a