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: In what African country did Italy see a collapse in 1942? Passage:At the beginning of 1943, Italy was facing defeat. The collapse of the African front on 4 November 1942 and the Allied landings in North Africa on 8–12 November exposed Italy to an invasion of the Allied forces. The defeat of the Italian expeditionary force (ARMIR) in Russia, the heavy bombings of the cities, and the lack of food and fuel demoralized the population, the majority of whom wanted to end the war and denounce the alliance with Germany. Italy needed German aid in order to maintain control of Tunisia, the last stronghold of the Axis powers in Africa. Italy's Duce, Benito Mussolini, was persuaded that the war could be decided in the Mediterranean theater. On 29 April 1943, at the meeting in Klessheim, Hitler rejected Mussolini's proposition to seek a separate peace with Russia and move the bulk of the German Army south. The request for reinforcements to defend the bridgehead in Tunisia was refused by the Wehrmacht, which no longer trusted the Italian will to maintain resistance. Mussolini's health was another main factor of uncertainty. He was depressed and sick after being diagnosed with gastritis and duodenitis of a nervous origin. Because of his illness, the Duce was often forced to stay at home, depriving Italy of effective government.
 Links: a. Second Battle of El Alamein b. Gastritis c. Axis powers d. Italian Army in Russia
Example Output: a

Example Input: Question: In which U.S. state is Perlmutter's childhood neighborhood located? Passage:Perlmutter spent his childhood in the Mount Airy neighborhood of Philadelphia. He went to school in nearby Germantown; first Greene Street Friends School for the elementary grades, followed by Germantown Friends School for grades 7 through 12. He graduated with an AB in physics from Harvard magna cum laude in 1981 and received his PhD in physics from the University of California, Berkeley, in 1986. Perlmutter's PhD thesis titled "An Astrometric Search for a Stellar Companion to the Sun" described the development and use of an automated telescope to search for Nemesis candidates under Richard A. Muller. At the same time, he was using this telescope to search for Nemesis and supernovae, which would lead him to his award-winning work in cosmology. Perlmutter attributes the idea for an automated supernova search to Luis Alvarez, a 1968 Nobel laureate, who shared his idea with Perlmutter's research adviser.
 Links: a. Richard A. Muller b. Mount Airy, Philadelphia c. Richard A. Muller d. List of Nobel laureates in Physics
Example Output: b

Example Input: Question: How long had 20th Centuy Fox been established when they signed Holm to a movie contract? Passage:After she starred in the Broadway production of Bloomer Girl, 20th Century Fox signed Holm to a movie contract in 1946. She made her film debut that same year in Three Little Girls in Blue, making a startling entrance in a "Technicolor red" dress singing "Always a Lady," a belting Ado Annie-type song, although the character was different—a lady. In 1947 she won an Oscar and Golden Globe for Best Supporting Actress in Gentleman's Agreement. However, after another supporting role in All About Eve, Holm realized she preferred live theater to movie work, and only accepted a few select film roles over the next decade. The most successful of these were the comedy The Tender Trap (1955) and the musical High Society (1956), both of which co-starred Frank Sinatra. She starred as a professor-turned-reporter in New York City in the CBS television series Honestly, Celeste! (fall 1954) and was thereafter a panelist on Who Pays? (1959). She also appeared several times on ABC's The Pat Boone Chevy Showroom. 
 Links: a. Three Little Girls in Blue b. Bloomer Girl c. The Pat Boone Chevy Showroom d. 20th Century Fox
Example Output:
d