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.

Ex Input:
Question: How old was the commander in chief when he coordinated a massive anti-guerrilla operation? Passage:In 1970, 22-year-old Crespo had dropped out of IST and was eventually drafted into military service in the Portuguese Colonial War. He transferred to Mozambique where his military occupation was to check the cement cargoes from Beira to the Cahora Bassa Dam construction site, near Tete. Some time later, due to his good fluency in English, he was placed in the press office of Kaúlza de Arriaga, the commander in chief of the Portuguese Armed Forces in Mozambique, who had coordinated a massive anti-guerrilla operation against FRELIMO separatists in 1970 - the Gordian Knot Operation. While serving in the army, Crespo also entered the newly created School of Medicine of the University of Lourenço Marques where he would complete a number of academic disciplines but did not graduate. He also married Helen de Souza from Johannesburg, a South African woman with Portuguese ancestry who worked in genetics. After the Carnation Revolution left-leaning military coup at Lisbon in April 1974, fresh out of the troop, Crespo fled Mozambique for South Africa.
 Links: a. Portuguese Colonial War b. Tete, Mozambique c. Kaúlza de Arriaga d. Kaúlza de Arriaga

Ex Output:
c


Ex Input:
Question: Which aircraft had a longer operational lifespan in the Royal Canadian Air Force between the McDonnell CF-101 Voodoo and the Avro CF-100 Canuck? Passage:The McDonnell CF-101 Voodoo was an all-weather interceptor aircraft operated by the Royal Canadian Air Force and the Canadian Forces between 1961 and 1984. They were manufactured by the McDonnell Aircraft Corporation of St. Louis, Missouri for the United States Air Force (as F-101s), and later sold to Canada. CF-101s replaced the obsolete Avro CF-100 Canuck in the RCAF's all-weather fighter squadrons. The Voodoo's primary armament was nuclear AIR-2A Genie unguided air-to-air rockets, and there was significant political controversy in Canada about their adoption. Although they never fired a weapon in wartime, the CF-101 served as Canada's primary means of air defence from Quick Reaction Alert facilities at Canadian airbases. The CF-101s were retired in the 1980s and replaced with McDonnell Douglas CF-18 Hornet fighters. Many examples are preserved in museums and parks in Canada and the United States.
 Links: a. Avro Canada CF-100 Canuck b. Interceptor aircraft c. Interceptor aircraft d. Royal Canadian Air Force

Ex Output:
a


Ex Input:
Question: Which Frente! EP released in the 1990s sold the most copies? Passage:Frente! (or Frente) are an Australian alternative rock and folk-pop group which originally formed in 1989. The original line-up consisted of Simon Austin on guitar and backing vocals, Angie Hart on lead vocals, Tim O'Connor on bass guitar (later replaced by Bill McDonald), and Mark Picton on drums (later replaced by Alastair Barden, then by Pete Luscombe). In August 1991 they issued their debut extended play, Whirled, which included the track, "Labour of Love". In March 1992 they released a second EP, Clunk, with its featured track, "Ordinary Angels", which peaked at No. 3 on the ARIA Singles Chart. It was followed in October by "Kelly Street" (unintentional misprint of "Accidentally Kelly Street" was retained) which reached No. 4. Their debut album, Marvin the Album, issued in November, peaked at No. 5 on the ARIA Albums Chart. "Labour of Love" was released as an EP outside of Australasia in 1994 as a CD single with a cover version of New Order's "Bizarre Love Triangle" included. The Australian rock music historian Ian McFarlane felt that the group's "quirky, irreverent, acoustic-based sound was at odds with the usual guitar-heavy, grunge trends of the day. The band's presentation had a tweeness about it that could have been off-putting if not for its genuine freshness and honesty".
 Links: a. Whirled (EP) b. Alternative rock c. Whirled (EP) d. Folk music

Ex Output:

a