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: What city did Empire Nightingale arrive in on July 1? Passage:Empire Nightingale would appear to have crossed the Atlantic Ocean from the United States independently, as she does not appear as a member of a convoy until 27 June, when she departed Middlesbrough, Yorkshire as a member of Convoy EC 31. The convoy had departed from Southend, Essex the previous day and arrived at the Clyde on 1 July. She left the convoy at Oban, Argyllshire, departing on 3 July for Baltimore, Maryland, United States, which was reached on 22 July. Empire Nightingale departed Baltimore on 10 August for Halifax, Nova Scotia, Canada, arriving five days later. Carrying a cargo of steel, she departed on 21 August with Convoy HX 146, which arrived at Liverpool, Lancashire on 6 September. She left the convoy at Loch Ewe to join Convoy WN 177, which departed from Oban on 5 September and arrived at Methil, Fife on 8 September. Empire Nightingale then joined Convoy FS 589, which departed that day and arrived at Southend on 10 September. She left the convoy at Hull, Yorkshire on 10 September.
Links: a. Halifax, Nova Scotia b. River Clyde c. Southend-on-Sea d. Southend-on-Sea
Example Output: b

Example Input: Question: During what years was the Early Bronze Age? Passage:Iran is home to one of the world's oldest continuous major civilizations, with historical and urban settlements dating back to 7000 BC. The south-western and western part of the Iranian Plateau participated in the traditional Ancient Near East with Elam, from the Early Bronze Age, and later with various other peoples, such as the Kassites, Mannaeans, and Gutians. Georg Wilhelm Friedrich Hegel calls the Persians the "first Historical People". The Medes unified Iran as a nation and empire in 625 BC. The Achaemenid Empire (550330 BC), founded by Cyrus the Great, was the first true global superpower state and it ruled from the Balkans to North Africa and also Central Asia, spanning three continents, from their seat of power in Persis (Persepolis). It was the largest empire yet seen and the first world empire. The Achaemenid Empire was the only civilization in all of history to connect over 40% of the global population, accounting for approximately 49.4 million of the world's 112.4 million people in around 480 BC. They were succeeded by the Seleucid, Parthian, and Sasanian Empires, who successively governed Iran for almost 1,000 years and made Iran once again as a leading power in the world. Persia's arch-rival was the Roman Empire and its successor, the Byzantine Empire.
Links: a. Bronze Age b. Cyrus the Great c. Persepolis d. Central Asia
Example Output: a

Example Input: Question: Who is the CEO of the airline that scheduled flights to several Florida cities and Detroit? Passage:In later years, Continental Express continued to serve the airport with nonstop regional jet flights to Cleveland while Continental Connection was operating nonstop turboprop flights to Albany, NY; however, both services ended in 2005. Spirit Airlines scheduled flights to several Florida cities and Detroit, before moving to LaGuardia Airport in 2001; in May 2008 the airline resumed service to Fort Lauderdale from MacArthur only to drop it soon after. Delta Express, which had nonstops to Orlando and Fort Lauderdale, dropped MacArthur Airport in 2003 after a decline in traffic. Delta Connection regional jet service to Atlanta flown by Atlantic Southeast Airlines (ASA) on behalf of Delta Air Lines ended on May 1, 2008 following a mid-April announcement that Delta and Northwest Airlines were planning to merge a move that led to changes for the merged airline.
Links: a. Detroit b. Atlanta c. Spirit Airlines d. Fort Lauderdale, Florida
Example Output:
c