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 often are new issues of the Canadian Journal of Neurological Sciences published? Passage:Multi-dose versions of the vaccine contain the preservative thiomersal (also known as thimerosal), a mercury compound that prevents contamination when the vial is used repeatedly. Single-dose versions and the live vaccine do not contain this preservative. In the U.S., one dose from a multi-dose vial contains approximately 25 micrograms of mercury, a bit less than a typical tuna fish sandwich. In Canada, different variants contain five and 50 micrograms of thimerosal per dose. The use of thiomersal has been controversial, with claims that it can cause autism and other developmental disorders. The U.S. Institute of Medicine examined these claims and concluded in 2004 that the evidence did not support any link between vaccines and autism. Other reviews came to similar conclusions, with a 2006 review in the Canadian Journal of Neurological Sciences stating that there is no convincing evidence to support the claim that thimerosal has a causal role in autism, and a 2009 review in the journal Clinical Infectious Diseases stating that claims that mercury can cause autism are "biologically implausible". The U.K. National Health Service stated in 2003 that "There is no evidence of long-term adverse effects due to the exposure levels of thiomersal in vaccines." The World Health Organization concluded that there is "no evidence of toxicity in infants, children or adults exposed to thiomersal in vaccines". Indeed, in 2008 a review noted that even though thiomersal was removed from all US childhood vaccines in 2001, this has not changed the number of autism diagnoses, which are still increasing.
Links: a. Thiomersal and vaccines b. Autism c. Canadian Journal of Neurological Sciences d. National Academy of Medicine
Example Output: c

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 Schafer of Austria also successfully defended his men's singles figure skating title from Lake Placid. Sweden swept the medals in the cross-country 50km, 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 Oddbjrn 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: How much higher was the winning score of the tournament that Ariana won the all-around silver for? Passage:In 2016, Arina began her season competing at the 2016 Grand Prix Moscow taking third place in the all-around, in apparatus finals: she won gold in ribbon and silver in clubs. On March 1720, Arina then competed at the 2016 Lisboa World Cup where she finished 5th in the all-around with a total of 70.400 points, she qualified 2 event finals taking silver in ribbon (tied with teammate Aleksandra Soldatova) and placed 4th in ball. At the 30th Thiais Grand Prix event in Paris, Arina finished 5th in the all-around and qualified 2 apparatus finals finishing 4th in clubs and ribbon. Arina finished 4th in the all-around at the 2016 Russian Championships held in Sochi. In May 68, Arina competed at the Brno Grand Prix where she finished 5th in the all-around behind Victoria Veinberg Filanovsky. On May 1315, Arina won the all-around silver at the Bucharest Grand Prix with a total of 73.600 points, she qualified to all apparatus finals: taking silver in ball, bronze in clubs, ribbon and 4th in hoop. On May 2729, Arina finished 4th in the all-around at the 2016 Sofia World Cup with a total of 73.450 points, she qualified to all apparatus finals and won bronze in hoop, clubs, placed 4th in ball, 7th in ribbon. On July 13, Arina competed at the 2016 Berlin World Cup however, she withdrew after the first day of qualifications because she suffered a hand injury. On September 2224, Arina competed at the 2016 Grand Prix Final in Eilat, Israel where she won the all-around bronze medal with a total of 73.916 points, she qualified in 2 apparatus finals taking silver medals in hoop and ribbon.
Links: a. Victoria Veinberg Filanovsky b. Paris c. 2016 FIG Rhythmic Gymnastics World Cup series d. Rhythmic Gymnastics Grand Prix
Example Output:
d