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: what sum of money will produce rs. 80 as simple interest in 4 years at 3 1 / 2 percent ?
Options: a. 263, b. 571.4, c. 367, d. 368, e. 339

Ex Output:
b


Ex 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

Ex Output:
e


Ex Input:
Problem: the ratio of the present age of viju to that of aju is 7: 2. 4 years from now, the ratio of the ages of viju to aju will be 5: 2. what was viju age 5 years ago ? ( rbi assistant 2015 )
Options: a. 24, b. 18, c. 12, d. 16, e. 13

Ex Output:

d