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 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: the total age of a and b is 12 year more than the total age of b and c. c is how many years younger than a ?
Options: a. 12, b. 24, c. data inadequate, d. none of these, e. 34

Output: a


Input: Consider Input: Problem: a bullet train 160 m long is running with a speed of 70 kmph. in what time will it pass a man who is running at 8 kmph in the direction opposite to that in which the bullet train is going ?
Options: a. 23 sec, b. 15 sec, c. 7.38 sec, d. 6.92 sec, e. 16 sec


Output: c