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 x ^ 2 – 4 x = 5, then one possible value of x – 2 =
Options: a. - 9, b. - 5, c. - 3, d. - 1, e. 5

Ex Output:
c


Ex Input:
Problem: what is the greatest positive integer n such that 3 ^ n is a factor of 36 ^ 100 ?
Options: a. 100, b. 200, c. 300, d. 600, e. 900

Ex Output:
b


Ex Input:
Problem: if the average of 5 positive integers is 50 and the difference between the largest and the smallest of these 5 numbers is 10, what is the maximum value possible for the largest of these 5 integers ?
Options: a. 50, b. 58, c. 49, d. 48, e. 44

Ex Output:

b