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: a merchant marks his goods up by 30 % and then offers a discount of 10 % on the marked price. what % profit does the merchant make after the discount ?
Options: a. 17 %, b. 25 %, c. 69 %, d. 31 %, e. 19 %

Ex Output:
a


Ex Input:
Problem: 11 is subtracted from 40 % of a number and results is 23. what is the number ?
Options: a. 160, b. 92, c. 88, d. 85, e. 34

Ex Output:
d


Ex Input:
Problem: a certain rectangular window is ( 1 / 3 ) times as long as it is wide. if its perimeter is 28 feet, what are its dimensions in terms of length by width ?
Options: ['a. 12 by 2', 'b. 11 by 3', 'c. 10.5 by 3.5', 'd. 10 by 4', 'e. 9 by 3']

Ex Output:

c