Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.

Ex Input:
Problem: if 12 machine can finish a job in 40 days, then how many more machines would be needed to finish the job in one - fourth less time ?
Options: a. a. 4, b. b. 8, c. c. 10, d. d. 12, e. e. 16

Ex Output:
a


Ex Input:
Problem: what is the smallest number by which 2880 must be divided in order to make it into a perfect square ?
Options: a. 3, b. 4, c. 5, d. 6, e. 7

Ex Output:
c


Ex Input:
Problem: for what value of x between − 7 and 7, inclusive, is the value of x ^ 2 − 10 x + 16 the greatest ?
Options: a. − 7, b. − 2, c. 0, d. 2, e. 7

Ex Output:

a