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 copies did "My Generation" sell the year it was released? Passage:A deliberate use of acoustic feedback was pioneered by Blues and Rock'n'Roll guitarists such as Willie Johnson, Johnny Watson and Link Wray. According to AllMusic's Richie Unterberger, the very first use of feedback on a commercial rock record is the introduction of the song "I Feel Fine" by the Beatles, recorded in 1964. Jay Hodgson agrees that it was the first chart-topper to showcase feedback distortion, created by John Lennon leaning a semi-acoustic guitar against an amplifier. The Who's 1965 hits "Anyway, Anyhow, Anywhere" and "My Generation" featured feedback manipulation by Pete Townshend, with an extended solo in the former and the shaking of his guitar in front of the amplifier to create a throbbing noise in the latter. Canned Heat's "Fried Hockey Boogie" (off of their 1968 album Boogie with Canned Heat) also featured guitar feedback produced by Henry Vestine during his solo to create a highly amplified distorted boogie style of feedback. In 1963, the teenage Brian May and his father custom-built his signature guitar Red Special, which was purposely designed to feed back.
Links: a. Anyway, Anyhow, Anywhere b. My Generation c. Boogie with Canned Heat d. Johnny "Guitar" Watson
Example Output: b

Example Input: Question: How large was the endowment at Durham University the year that Mitchell started attending the school? Passage:Mitchell was born in London, and educated at Brightlands Preparatory School and Dulwich College, London. In 1943 he registered as a conscientious objector and his war-time service was spent in the Non-Combatant Corps. After the war, he taught at Oakfield Preparatory School, London and in 1947 founded and edited the journal Music Survey; several issues appeared before he was joined in 1949 by Hans Keller and the journal was re-launched in the Music Survey's so-called 'New Series' (194952), whose uncompromising critical standards and pugnaciously pro-Britten and pro-Schoenberg stance brought it renown and notoriety in equal measure. Mitchell studied at Durham University 1949-50. In the 1950s he was a regular contributor to the journals Musical Times and Musical Opinion. In 1958 he became editor of Music Books at Faber and Faber and in the same year was appointed Editor of Boosey & Hawkes's music journal Tempo, until 1962. From 1963 to 1964 he was a special music adviser at Boosey & Hawkes with particular responsibility for contemporary music and the acquisition of contemporary composers. He was responsible for Peter Maxwell Davies and Nicholas Maw joining the publisher's list. In 1965, with the encouragement of Benjamin Britten he founded the music-publishing firm of Faber Music, and was its first Managing Director (vice-chairman, 1976, chairman, 1977, president, 198895). In 1972 he became the first Professor of Music at Sussex University (until 1976). Following the death of Benjamin Britten, Mitchell became a senior trustee of the Britten-Pears Foundation; in 1986 he became the Foundation's director and chairman of the Britten Estate Ltd. From 1989 to 1992 he was chairman of the Performing Right Society. He was appointed a CBE in the 2000 New Year Honours, and died on 28 September 2017.
Links: a. Non-Combatant Corps b. Oakfield Preparatory School c. Nicholas Maw d. Durham University
Example Output: d

Example Input: Question: How many other battalions were involved in Operation Michael during the time period that the Wiltshire Regiment was involved? Passage:Upon mobilization and the declaration of war, the 1st Battalion, Wilts deployed to France as part of the 3rd Division's 7th Brigade, landing in France on 14 August 1914, and soon fought in the Battle of Mons and the Great Retreat and, in October, in the First Battle of Ypres, by which time the battalion had lost 26 officers and over 1,000 other ranks. The 1st Wilts remained on the Western Front with the 3rd Division until the 7th Brigade was transferred to the 25th Division on 18 October 1915. In March 1918 the battalion was involved in Operation Michael, the opening phase of the German Army's Spring Offensive, and subsequently reduced to company strength. It was during this fighting that Acting Captain Reginald Frederick Johnson Hayward MC was awarded the Victoria Cross. The 1st Wilts served with the 25th Division until was transferred on 21 June 1918. On 21 June 1918, the 1st Wilts joined the 110th Brigade, part of the 21st Division, with which it served for the rest of the war.
Links: a. Military Cross b. Company (military unit) c. Operation Michael d. Great Retreat
Example Output:
c