Given the task definition and input, reply with output. 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.

Question: How many year's after the creation of Yale did Henry M. Hoenigswald serve as a research assistant? Passage:He was educated in the German Gymnasium, where he learned the classical languages, and trained as an Indo-Europeanist and a historical and comparative linguist in universities in Munich, Zurich, Padua, and Florence. His refugee status compelled these moves (his grandparents were Jewish, and by 1933 Jews were forbidden to attend German universities). In 1939 he escaped to the United States, where he was at first a research assistant at Yale. He taught at the University of Pennsylvania from 1948 until his retirement in 1985. He was a member of the Linguistic Society of America, of which he was elected President in 1958, and a member of the American Philosophical Society for more than 30 years. He was elected to the National Academy of Sciences. He spent a year at Oxford in 1976 and was elected a Corresponding Fellow of the British Academy in 1986.
 Links: a. Yale University b. Yale University c. Gymnasium (Germany) d. University of Oxford

a