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 members did No. 11 Group have during the years of the Blitz? Passage: the Second World War, the station was very active during the Battle of Britain and the Blitz in 1940–41 in No. 12 Group (controlled from RAF Watnall in Nottingham) as it was the main fighter station for a lot of the southern East Midlands, and fighters from the station would often patrol as far as Birmingham. During the Battle of Britain many squadrons were rotated through Wittering to spells in the south of England with No. 11 Group that was bearing the brunt of the battle. With many of the Luftwaffe raids during the Blitz taking part at night, Wittering-based squadrons were instrumental in the development of night combat techniques. These included the use of the Turbinlite aircraft which replaced the nose with a powerful searchlight insulated in the nose of Havocs and Bostons. In April 1943 No. 141 Squadron were moved in, operating de Havilland Mosquitoes. 1943 also saw the station host 2 USAAF squadrons, albeit temporarily: 63 Fighter Squadron USAAF with its P47s operated from Wittering between January and March before moving to RAF Horsham St Faith; 55 Fighter Squadron operated its P38s and P51s from Wittering between August and March 1944 before moving to nearby RAF Kingscliffe.
 Links: a. No. 11 Group RAF b. Birmingham c. Birmingham d. 63rd Fighter Squadron
Example Output: a

Example Input: Question: What was Michael Caine's first film role when his acting career began in the 1950s? Passage:Michael Caine is an English actor who has appeared in over 130 films and has had multiple television appearances. Caine's acting career began in the 1950s, when he was cast in many small, often uncredited roles in British films. Caine gained recognition as one of the most famous actors of the 1960s through his breakthrough role in the film Zulu (1964). He then portrayed spy Harry Palmer in the films The Ipcress File (1965), Funeral in Berlin (1966) and Billion Dollar Brain (1967). He also had starring roles in The Italian Job and Battle of Britain (both 1969). His role in Sleuth (1972) led him to an Academy Award for Best Actor nomination. Caine has won a Best Supporting Actor Oscar for the films Hannah and Her Sisters (1986) and The Cider House Rules (1999). More recently, Caine has gained a new following through his collaborations with British-American filmmaker Christopher Nolan in the Dark Knight Trilogy films, as well as Inception (2010) and Interstellar (2014).
 Links: a. Michael Caine b. Michael Caine c. Funeral in Berlin (film) d. Inception
Example Output: a

Example Input: Question: How old was Alikhanov when Pomeranchuk studied with him? Passage:After Landau moved to the Kapitza institute in Moscow (to avoid arrest for comparing Stalinism to Nazism), Pomeranchuk also moved there, working for the tanning industry. He returned to Leningrad in 1938, lecturing, completing his Ph.D. and becoming employed as a junior scientist. He joined the Lebedev Institute of the Academy of Sciences of the USSR in Moscow as a senior scientist in 1940. In 1941 the institute was evacuated to Kazan. Under Abraham Alikhanov, he studied cosmic rays in Armenia from 1942. In 1943, he transferred to Laboratory No.2 under Igor Kurchatov as part of the Soviet project to develop nuclear weapons. Alikhanov founded Laboratory No.3 (which became the Institute for Theoretical and Experimental Physics (ITEP)) and Pomeranchuk worked there from 1946 (and for the rest of his life), founding and leading the Theoretical department, as well as being Professor of Theoretical Physics at the Moscow Mechanical Institute where students admired his infectious enthusiasm for his subject. Rudolf Peierls was consoled by the fact that it was "very clever Pomeranchuk" - and no-one else - who corrected his 1/T law for heat conduction in high-temperature condensed matter physics. His work in the 1940s was dominated by neutron research and his manuscript with Akhiezer was the basic guide for Soviet nuclear reactor construction. In 1950, he published a paper suggesting that the entropy of helium-3 as a liquid was less than as a solid. In 1950, Pomeranchuk received an order from Josef Stalin to go to Arzamas-16, located in the closed city of Sarov, Nizhny Novgorod region, to work on Soviet nuclear weaponry. Missing his family and his 'hobby physics' problems, he was advised not to apply for a revocation but wait until the order was "forgotten." He returned to ITEP within a year. He continued enthusiastically with work on quantum field theory and S-matrix theory, particle collisions and Regge theory, the latter in vigorous collaboration with Vladimir Gribov. His last paper on Regge theory was published posthumously. For his work, Pomeranchuk was twice awarded the Stalin Prize (1950, 1952). He was elected a corresponding member of the Academy of Sciences of the USSR in 1953 and full member in 1964.
 Links: a. S-matrix theory b. Abraham Alikhanov c. USSR State Prize d. Nazism
Example Output:
b