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: Was the song The Great Gig in the Sky released as a single? Passage:The record builds on ideas explored in Pink Floyd's earlier recordings and performances, while omitting the extended instrumentals that characterised their earlier work. A concept album, its themes explore conflict, greed, time, death, and mental illness, the latter partly inspired by the deteriorating health of founding member Syd Barrett, who departed the group in 1968. The group used recording techniques such as multitrack recording, tape loops, and analogue synthesisers. Snippets from interviews with the band's road crew, as well as philosophical quotations, were also used. Engineer Alan Parsons was responsible for many sonic aspects and the recruitment of singer Clare Torry, who appears on "The Great Gig in the Sky". The sleeve, which depicts a prism spectrum, was designed by Storm Thorgerson, following keyboardist Richard Wright's request for a "simple and bold" design, representing the band's lighting and the record's themes. The album was promoted with two singles: "Money" and "Us and Them".
Links: a. Keyboardist b. Mental disorder c. The Great Gig in the Sky d. Keyboardist
Output:
c