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.

Example Input: Problem: how many quarters are equal to 7 dollars ?
Options: a. 1, b. 28, c. 12, d. 9, e. 7
Example Output: b

Example Input: Problem: there are 27 different 3 - digit integers that can be formed using only the digits 3, 4 and 5. if all 27 of the integers were listed, what would their sum be ?
Options: a. 11,888, b. 11,988, c. 12,088, d. 12,188, e. 12,288
Example Output: b

Example Input: Problem: 1 / 2,16, 4,15, 3,56, _ ?
Options: a. 28 / 3, b. 27 / 3, c. 26 / 3, d. 25 / 3, e. 24 / 3
Example Output:
a