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: Who did Hungary defeat to become Central European Champions in 1953? Passage:Budai made his debut for Hungary on 2 May 1949 in a 6-1 win against Austria in the Central European Championship. He subsequently played 39 times for Hungary and scored 10 goals. Four of these goals came in a 12-0 win against Albania on 24 September 1950. As one of the legendary Mighty Magyars, he helped Hungary become Olympic Champions in 1952 and Central European Champions in 1953. He also played in the Hungary side that defeated England 6-3 at Wembley Stadium. During the 1954 FIFA World Cup he played in the group stage in the 9-0 win against South Korea and in the semi-final against Uruguay. However, despite an excellent performance in the latter game, he was dropped for the final to make room for Ferenc Puskás. He also played two games at the 1958 World Cup.
 Links: a. Match of the Century (1953 England v Hungary football match) b. Match of the Century (1953 England v Hungary football match) c. Austria national football team d. Central European International Cup

Ex Output:
d


Ex 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

Ex Output:
d


Ex Input:
Question: How many years after the discovery of pulsars did Lyne retire? Passage:Andrew Geoffrey Lyne FRS (born 13 July 1942) is a British physicist. Lyne is Langworthy Professor of Physics in the School of Physics and Astronomy, University of Manchester, as well as an ex-director of the Jodrell Bank Observatory. Despite retiring in 2007 he remains an active researcher within the Jodrell Bank Pulsar Group. Lyne was educated at The Portsmouth Grammar School, the Royal Naval School, Tal Handaq, Malta and at St. John's College at the University of Cambridge (natural sciences), continuing to the University of Manchester for a PhD in Radio Astronomy. Lyne writes that he is "mostly interested in finding and understanding radio pulsars in all their various forms and with their various companions. Presently, I am most occupied with the development of new multibeam search systems at Jodrell and Parkes, in order to probe deeper into the Galaxy, particularly for millisecond pulsars, young pulsars and any that might be in binary systems."
 Links: a. Radio astronomy b. Portsmouth Grammar School c. Pulsar d. Pulsar

Ex Output:

c