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: Who was older, Tian Chengsi or Li Baochen? Passage:By 775, one of the military governors who had only nominally been submissive to Emperor Daizong, Tian Chengsi the military governor of Weibo Circuit (魏博, headquartered in modern Handan, Hebei), had particularly offended not only the imperial government but also his fellow warlords—by seizing much of Zhaoyi Circuit (昭義, headquartered in modern Anyang, Henan) after the death of its military governor Xue Song in 773; by looking down on Li Zhengji the military governor of Pinglu Circuit (平盧, headquartered in modern Tai'an, Shandong) and Li Baochen the military governor of Chengde (成德, headquartered in modern Shijiazhuang, Hebei); and by killing Li Baochen's brother Li Baozheng (李寶正), who was also his son-in-law, after his own son Tian Wei (田維) died after colliding with Li Baozhen while playing polo. Li Baochen and Li Zhengji thus offered to attack Tian, and Emperor Daizong decided to take this opportunity to destroy the rebellious Tian. As Zhu Tao was then submissive to the imperial government, he joined forces with Li Baochen and another general loyal to the imperial government, Xue Jianxun (薛兼訓), to attack Weibo from the north, while Li Zhengji and Li Zhongchen attacked from the south. The joint forces had initial successes, but when Zhu and Li Baochen attacked Cang Prefecture (滄州, in modern Cangzhou, Hebei), which was defended by Tian's cousin Tian Tingjie (田庭玠), they could not capture it quickly. Meanwhile, Tian Chengsi had persuaded Li Zhengji to withdraw with flattery. In addition, Li Baochen was offended when an imperial eunuch, Ma Chengqian (馬承倩), who had visited Li Baochen's army, was so dissatisfied with Li Baochen's gift to him that he threw it on the ground, and Tian was also able to use hoaxes to persuade Li Baochen that if he joined forces with Tian to attack Lulong, he would be successful. Li Baochen thus turned against Zhu, launching a surprise attack on him, but was unable to kill Zhu, effectively ending any hopes of the campaign against Tian and subsequently creating an enmity between the Chengde and Lulong Circuits. Emperor Daizong was subsequently forced to reaccept Tian Chengsi's nominal submission.
 Links: a. Tai'an b. Polo c. Shandong d. Li Baochen
Example Output: d

Example Input: Question: What was Montana's population the year that Thom Ross completed his work "Custer's Last Stand"? Passage:Ross' first plywood installation was a 1976 cutout of Clint Eastwood, which he and a friend placed as a prank above a railroad trestle to recreate a scene from Dirty Harry in the location where the scene had been filmed five years earlier. In 1983 Ross created "154 Nevermore", an installation of 154 plywood ravens on a highway in Jackson, Wyoming (recreated in steel in 2000). In 1984, Ross created "the Catch", a diorama for the Baseball Hall of Fame illustrating a legendary catch with the same nickname, by Willie Mays in the 1954 World Series. He created a new version of the work in 2004, and displayed it in various locations in New York City. In 1998 Ross created "The Defining Moment" for SAFECO Field, a tableau of 11 steel cutouts of a Ken Griffey, Junior play in the 1995 baseball playoffs. Ross' 2005 work, "Custer's Last Stand", was a recreation of life-sized warriors riding life-sized horses the Battle of Little Bighorn at the original site at Medicine Tail Coulee in Montana. That exhibit toured Cody, Wyoming, Jackson, Wyoming, and Sun Valley, Idaho. In September, 2008 Ross recreated a 1902 photograph of Buffalo Bill Cody and his "Wild West Show", his traveling troupe of Native Americans, in front of the Cliff House at Ocean Beach.
 Links: a. National Baseball Hall of Fame and Museum b. Battle of the Little Bighorn c. Montana d. T-Mobile Park
Example Output: c

Example Input: Question: What was the nationality of the person that Oldfield compared himself to? Passage:Oldfield, an Australian national, said he was making "a protest against inequalities in British society, government cuts, reductions in civil liberties and a culture of elitism". Oxford number two, William Zeng, denounced Oldfield and described him as "a mockery of a man", while Oxford boat club president Karl Hudspith tweeted "my team went through seven months of hell, this was the culmination of our careers and [Oldfield] took it from us". Educated at the Sydney Church of England Grammar School, the University of Sydney and the London School of Economics, and Fellow of the Royal Society of Arts, Oldfield tweeted the day after the race, "Having been deep within elite institutions I have a very good understanding of them. I protest their injustices – ask anyone that knows me". On his blog, Oldfield compared his actions to those of Emily Davison, the suffragette killed after stepping in front of the King's horse at The Derby in 1913. Despite later stating he had some sympathy for both the rowers and spectators, he said he had no regrets and that he "would have felt less of a man" had he not made the protest. In October 2012, Oldfield was jailed for six months for causing a public nuisance and ordered to pay £750 costs. In June 2013, he was refused leave to remain in the United Kingdom, the Home Office claiming his presence there was not "conducive to the public good". Oldfield, whose wife is from India, appealed on the grounds that she would be threatened in Australia, and in December 2013, the deportation order was overturned. Security for the 2013 race was increased as a result of Oldfield's actions, with Royal Marines, additional stewards and the Metropolitan Police Marine Policing Unit in attendance.
 Links: a. The Boat Race 2013 b. Emily Davison c. Indefinite leave to remain d. University of Sydney
Example Output:
b