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 5 a = 3125, then the value of 5 ( a - 3 ) is :
Options: a. 25, b. 125, c. 625, d. 1625, e. none of these

Ex Output:
a


Ex Input:
Problem: the total age of a and b is 15 years more than the total age of b and c. c is how many year younger than
Options: a. 14 years, b. 12 years, c. 56 years, d. 66 years, e. 15 years

Ex Output:
e


Ex Input:
Problem: what is the remainder when 1201 × 1202 × 1204 × 1205 is divided by 6 ?
Options: a. 1, b. 2, c. 3, d. 4, e. 5

Ex Output:

d