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.

Input: Consider Input: Problem: find the maximum value of the function f ( x ) = x − 5 if x is a number between - 5 and 13.
Options: a. 6, b. 7, c. 8, d. 9, e. none

Output: c


Input: Consider Input: Problem: there are 7 pairs of socks and 2 socks are worn from that such that the pair of socks worn are not of the same pair. what is the number of pair that can be formed.
Options: a. 40, b. 49, c. 41, d. 56, e. 42

Output: e


Input: Consider Input: Problem: in a certain country 1 / 5 of 8 = 4. assuming the same proportion, what would be the value of 1 / 4 of 16 ?
Options: a. 13, b. 12, c. 10, d. 16, e. 14


Output: c