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: How old was Richard when Filip began working with him? Passage:He was the son of a merchant, Adolf Abraham Eisenberg, and Ester née Spiro. After finishing Sobieski Gymnasium in Kraków he studied medicine at the Jagiellonian University, where he obtained his PhD in medical studies in 1899. He then conducted postgraduate work in Vienna with Richard Paltauf and between 1901 and 1902 served as a research assistant to Odo Bujwid. Subsequently he worked in Paris, at the Pasteur Institute and then in Wrocław (Breslau) under the direction of Richard Pfeiffer. Between 1919 and 1920 he was the head of a Military Hospital in Warsaw. In 1933 he became the director of the National Bacteriology Station in Kraków, a position he held until 1939. Until 1941 he was the head of the Institute of Medical Microbiology in Lwów (L'viv).
 Links: a. Richard Paltauf b. Odo Bujwid c. Richard Friedrich Johannes Pfeiffer d. Odo Bujwid
Example Output: a

Example Input: Question: Who was the leader of Hungary during the Hungarian Revolution of 1848? Passage:The last meetings had revealed the rising antagonism with Britain and France, especially on Italian unification, the right to self-determination and the Eastern Question. The Alliance is conventionally taken to have become defunct with Alexander's death in 1825. France ultimately went her separate way after the July Revolution of 1830, leaving the core of Russia, Austria and Prussia as Central-Eastern European block which once again congregated to suppress the Revolutions of 1848. The Austro-Russian alliance finally broke up in the Crimean War: though Russia had helped to completely destroy the Hungarian Revolution of 1848, Austria did not take any action to support her ally, declared herself neutral and even occupied the Wallachian and Moldavian lands on the Danube upon the Russian retreat in 1854. Thereafter, Austria remained isolated, which added to the loss of her leading role in the German lands, culminating in the defeat of the Austro-Prussian War in 1866.
 Links: a. Eastern Europe b. Hungarian Revolution of 1848 c. Danube d. Wallachia
Example Output: b

Example Input: Question: Who is the oldest band that Eric listens to? Passage:Eric is a well-known fan of science fiction, such as  and especially Star Wars, in which he compares himself to Luke Skywalker. He is also known to have a large, beloved collection of G.I. Joe. He listens to artists such as Led Zeppelin, KISS, Aerosmith, Pink Floyd, Lynyrd Skynyrd, Deep Purple, Queen, Styx and Rush. He is also a Beatles fan and has been known to liken his group of friends to them, accusing Jackie of "breaking up the band" with her romantic entanglements with Kelso and Hyde (calling her Yoko, in reference to Yoko Ono). It is also hinted that he is both a Batman and Spider-Man fan, having Spider-Man bed sheets and a considerable number of comic books, most of them bearing the Marvel Comics logo with the titular character on the covers. When he fights a fan at the Packers game, he tells Red that he learned his moves from Spider-Man; coincidentally, Topher Grace starred as Eddie Brock, a character who obtains powers very similar to Spider-Man, thus transforming him into the monstrous Venom in Spider-Man 3 in 2007.
 Links: a. Deep Purple b. Led Zeppelin c. Lynyrd Skynyrd d. Deep Purple
Example Output:
b