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 fruit - salad mixture consists of apples, peaches, and grapes in the ratio 6: 5: 4, respectively, by weight. if 60 pounds of the mixture is prepared, the mixture includes how many more pounds of apples than grapes ?
Options: a. 15, b. 12, c. 8, d. 6, e. 4

Ex Output:
c


Ex Input:
Problem: a furniture dealer purchased a desk for $ 150 and then set the selling price equal to the purchase price plus a markup that was 40 % of the selling price. if the dealer sold the desk at the selling price, what was the amount of the dealer ' s gross profit from the purchase and the sale of the desk ?
Options: a. $ 40, b. $ 60, c. $ 80, d. $ 90, e. $ 100

Ex Output:
e


Ex Input:
Problem: the ratio of the volumes of two cubes is 1000: 1331. what is the ratio of their total surface areas ?
Options: a. 100: 121, b. 100: 127, c. 81: 191, d. 81: 161, e. 100: 182

Ex Output:

a