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 earned the bronze medal in the event where the Austrian athlete earned the gold? Passage:Sonja Henie of Norway won her third straight gold medal in the ladies' singles figure skating event, her last Olympic medal as she turned professional shortly after the Games. Karl Schäfer of Austria also successfully defended his men's singles figure skating title from Lake Placid. Sweden swept the medals in the cross-country 50 km, as did Norway in the Nordic combined. Norway's Ivar Ballangrud was the most successful athlete, winning three golds and a silver in speed skating and taking his career total to seven Olympic medals. Other multiple medal winners were Oddbjørn Hagen of Norway (one gold, two silvers), Ernst Baier of Germany (one gold, one silver), Joseph Beerli of Switzerland (one gold, one silver), Erik August Larsson of Sweden (one gold, one bronze), Birger Wasenius of Finland (two silvers, one bronze), Olaf Hoffsbakken of Norway (two silvers), Fritz Feierabend of Switzerland (two silvers) and Sverre Brodahl of Norway (one silver, one bronze).
 Links: a. Figure skating at the 1936 Winter Olympics – Men's singles b. Nordic combined at the 1936 Winter Olympics c. Fritz Feierabend d. Nordic combined at the 1936 Winter Olympics
Example Output: a

Example Input: Question: What languages did Commandino translate the works fo Aristarchus of Samos and Pappus of Alexandria from? Passage:Born in Urbino, he studied at Padua and at Ferrara, where he received his doctorate in medicine. He was most famous for his central role as translator of works of ancient mathematicians. In this, his sources were primarily written in Greek and secondarily in Arabic, while his translations were primarily in Latin and secondarily in Italian. He was responsible for the publication of many treatises of Archimedes. He also translated the works of Aristarchus of Samos (On the sizes and distances of the Sun and the Moon), Pappus of Alexandria (Mathematical collection), Hero of Alexandria (Pneumatics), Ptolemy of Alexandria (Planisphere and Analemma), Apollonius of Perga (Conics) and Euclid of Alexandria (Elements). Among his pupils was Guidobaldo del Monte and Bernardino Baldi. Commandino maintained a correspondence with the astronomer Francesco Maurolico. The proposition known as Commandino's theorem first appears in his work on centers of gravity.
 Links: a. Medicine b. Apollonius of Perga c. Aristarchus of Samos d. Medicine
Example Output: c

Example Input: Question: What was the runtime for the episode in which the doctor is shot twice? Passage:The regeneration of the Ninth Doctor into the Tenth at the end of "The Parting of the Ways" (2005) used computer effects to morph Christopher Eccleston into David Tennant. In the episode of Doctor Who Confidential accompanying the episode "Utopia" (2007), where the same effect is used for the Master's regeneration, it is stated that the production team decided that this would be a common effect for all future Time Lord regenerations, rather than each regeneration being designed uniquely at the whim of the individual director. This style of transition is seen again in "The Stolen Earth"/"Journey's End" (2008) both when the Doctor undergoes an aborted regeneration, and when his hand spawns a clone in the second part; in The End of Time (2010) during which Matt Smith took over the role as the Eleventh Doctor; in "The Impossible Astronaut" when the Doctor is shot twice and seemingly killed; in "Day of the Moon" when a young girl regenerates; and in "Let's Kill Hitler" when Mels (Nina Toussaint-White) is shot and regenerates into River Song (Alex Kingston). "The Night of the Doctor" and "The Day of the Doctor" subsequently use the effect to show the Eighth Doctor and War Doctor's regenerations respectively. The Eighth Doctor's regeneration into the War Doctor uses steady beams of light as opposed to the flame effect used for other revived series regenerations. In the Series 10 episode "The Lie of the Land", the Twelfth Doctor fakes a regeneration as part of a plan to test if Bill still has free will. The effect used is consistent with the one used in the modern series, with the Doctor's hands glowing and emitting regeneration energy before he enters full regeneration. However, as the regeneration was not real, it did not use up a regeneration and the Doctor did not change bodies.
 Links: a. The Impossible Astronaut b. The Lie of the Land c. Let's Kill Hitler d. The Impossible Astronaut
Example Output:
a