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: a cement mixture is composed of 3 elements. by weight, 1 / 2 of the mixture is sand, 1 / 5 of the mixture is water, and the remaining 15 pounds of the mixture is gravel. what is the weight of the entire mixture in pounds ?
Options: a. 30, b. 40, c. 50, d. 60, e. 80
Example Output: c

Example Input: Problem: on the independence day, bananas were be equally distributed among the children in a school so that each child would get two bananas. on the particular day 360 children were absent and as a result each child got two extra bananas. find the actual number of children in the school ?
Options: a. 237, b. 287, c. 197, d. 287, e. 720
Example Output: e

Example Input: Problem: a and b invests rs. 3000 and rs. 5500 respectively in a business. if a doubles his capital after 6 months. in what ratio should a and b divide that year ' s profit ?
Options: a. 8: 8, b. 9: 8, c. 9: 7, d. 9: 5, e. 9: 11
Example Output:
e