You will be given a definition of a task first, then some input of the task.
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 years had Ballantine Books been in business before it started published the series of annual paperback anthologies? Passage:The Best Science Fiction of the Year was a series of annual paperback anthologies edited by Terry Carr. It was published by Ballantine Books from 1972 to 1980, Pocket Books from 1981 to 1983, Baen Books in 1984, and Tor Books from 1985 to 1987. The Tor Books volumes bore the title Terry Carr's Best Science Fiction of the Year from 1985 to 1986, and Terry Carr's Best Science Fiction and Fantasy of the Year in 1987. Most volumes were also issued in hardcover in the United Kingdom by Gollancz, the last three under the variant title Best SF of the Year. The series was a continuation of the earlier anthology series World's Best Science Fiction, edited by Carr with Donald A. Wollheim, published from 1965 to 1971 by Ace Books. (Wollheim, with co-editor Arthur W. Saha, also issued his own separate continuation, The Annual World's Best SF, from 1972 to 1990.)
Links: a. Baen Books b. Ballantine Books c. Donald A. Wollheim d. Arthur W. Saha
Output:
b