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

Output: c


Input: Consider Input: Problem: if n = 2 ^ 0.15 and n ^ b = 1, b must equal
Options: a. 3 / 80, b. 20 / 3, c. 4, d. 5 / 3, e. 80 / 3

Output: b


Input: Consider Input: Problem: a 600 meter long train crosses a signal post in 40 seconds. how long will it take to cross a 7.2 kilometer long bridge, at the same speed ?
Options: a. 4 min, b. 2 min, c. 8 min, d. 9 min, e. 3 min


Output: c