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 long was Ron Hughes Commander? Passage:Dunstan was then posted to the 1st Battalion, Royal Australian Regiment (1 RAR) as second-in-command in 1953. He then saw service in Korea including a period as Military Assistant to the Commander in Chief of the British Commonwealth Forces Korea, and was appointed a Member of the Order of the British Empire in the 1954 New Year Honours. Between May 1964 and February 1965, Dunstan commanded 1 RAR, before later holding an appointment at the 1st Recruit Training Battalion. Having reached the rank of colonel, in early 1968 he was deployed to Vietnam as deputy commander of the 1st Australian Task Force (1 ATF). He took over from Brigadier Ron Hughes as Commander of the 1 ATF on 21 May 1968 during the Battle of CoralBalmoral. For his services during this battle, he was appointed a Commander of the Order of the British Empire in 1969.
Links: a. 1st Battalion, Royal Australian Regiment b. Order of the British Empire c. Brigadier d. 1954 New Year Honours

Ex Output:
b

Ex Input:
Question: What age was Robert I the year the Battle of Bannockburn occurred? Passage:Scottish field armies rarely managed to stand up to the usually larger and more professional armies produced by England, but they were used to good effect by Robert I of Scotland at the Battle of Bannockburn in 1314 to secure Scottish independence. He adopted a policy of slighting castles and made use of naval power to support his forces, beginning to develop a royal Scottish naval force. In the Late Middle Ages under the Stewart kings these forces were further augmented by specialist troops, particularly men-at-arms and archers, hired by bonds of manrent, similar to English indentures of the same period. New "livery and maintenance" castles were built to house these troops and castles began to be adapted to accommodate gunpowder weapons. The Stewarts also adopted major innovations in continental warfare, such as longer pikes, the extensive use of artillery, and they built up a formidable navy. However, one of the best armed and largest Scottish armies ever assembled still met with defeat at the hands of an English army at the Battle of Flodden in 1513, which saw the destruction of a large number of ordinary troops, a large section of the nobility and King James IV.
Links: a. Royal Scots Navy b. Scotland in the Late Middle Ages c. Manrent d. Robert the Bruce

Ex Output:
d

Ex Input:
Question: Comparing Ptacek's country of origin to the country to which he moved at age five, which has the lowest longitude? Passage:Ptacek was born in East Berlin to a family of Czech and German descent. His family fled East Germany for the United States when he was five years old. They eventually settled in Chicago, where young Ptacek was first exposed to blues music. He moved to Tucson in the early 1970s, where he began his own musical career, most often solo, but sometimes he plugged in and led a trio as Rainer & Das Combo. He co-founded Giant Sandworms with Howe Gelb in the late 1970s. When the band decided to move to New York and became Giant Sand, Ptacek opted to stay in Tucson to make sure that he would not disrupt his then-new family. Although he never became well known in the United States, he became more and more recognized in Europe. ZZ Top guitarist Billy Gibbons was so impressed with the singer-guitarist that he arranged to have Kurt Loder review Ptacek's "Mush Mind Blues" cassette in Rolling Stone. Ptacek later traveled to Houston at the invitation of Billy Gibbons to record at Gibbons' Gold Star Sound Services studio which saw release as "The Texas Tapes" meeting international attention and approval. Robert Plant, similarly impressed, flew Ptacek to England for the sessions for B-sides to supplement the singles from Fate of Nations.
Links: a. East Germany b. ZZ Top c. East Germany d. United States

Ex Output:
a