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.

Input: Consider Input: Question: How many species of the Aru Flying fox are there? Passage:Of the 62 flying fox species evaluated by the IUCN as of 2018, 3 are considered critically endangered: the Aru flying fox, Livingstone's fruit bat, and the Vanikoro flying fox. Another 7 species are listed as endangered; 20 are listed as vulnerable, 6 as near threatened, 14 as least concern, and 8 as data deficient. A further 4 are listed as extinct: the dusky flying fox, the large Palau flying fox, the small Mauritian flying fox, and the Guam flying fox. Over half of the species are threatened today with extinction, and in particular in the Pacific, a number of species have died out as a result of hunting, deforestation, and predation by invasive species. Six flying fox species are believed to have gone extinct from 1864 to 2014: the Guam, large Palau, small Mauritian, dusky, large Samoan, and the small Samoan flying foxes.
 Links: a. Endangered species b. Vanikoro flying fox c. Aru flying fox d. Critically endangered

Output: c


Input: Consider 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

Output: c


Input: Consider Input: Question: When did the Vietnam War end? Passage:Koreans in Vietnam is a community of Vietnam with a population of Korean expatriates along with Vietnamese citizens of Korean ancestry. The population initially came in a military capacity, fighting on both sides of the Vietnam War. After the end of the war, there was little Korean migration or tourism in Vietnam, until the rise of the South Korean economy and the decline of the North resulted in an influx of South Korean investors and North Korean defectors, as well as South Korean men seeking Vietnamese wives. As of 2011, according to statistics of South Korea's Ministry of Foreign Affairs and Trade, they numbered roughly eighty thousand people, making them the second-largest Korean diaspora community in Southeast Asia, after the Korean community in the Philippines, and the tenth-largest in the world. A more recent estimate from Vietnam Television says their population might be as large as 130,000.
 Links: a. Economy of South Korea b. Koreans c. Vietnam War d. Ministry of Foreign Affairs (South Korea)


Output: c