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 8 men or 12 women can do a piece of work in 30 days, in how many days can the same work be done by 6 men and 11 women ?
Options: a. 10 days, b. 11 days, c. 13 days, d. 15 days, e. 18 days

Output: e

Input: Consider Input: Problem: two pipes a and b can fill a tank in 36 hours and 46 hours respectively. if both the pipes are opened simultaneously, how much time will be taken to fill the tank ?
Options: a. 20.195 hrs, b. 21.195 hrs, c. 22.195 hrs, d. 23.195 hrs, e. 20.495 hrs

Output: a

Input: Consider Input: Problem: if @ is a binary operation defined as the difference between an integer n and the product of n and 5, then what is the largest positive integer n such that the outcome of the binary operation of n is less than 14 ?
Options: a. 1, b. 2, c. 3, d. 4, e. 5
Output: c