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: how much is 60 % of 40 is greater than 4 / 5 of 30 ?
Options: a. 8, b. 3, c. 7, d. 0, e. 1

Ex Output:
d


Ex Input:
Problem: the average runs scored by a batsman in 30 matches is 50. in the next 15 matches the batsman scored an average of 26 runs. find his average in all the 45 matches ?
Options: a. 31, b. 42, c. 29, d. 97, e. 27

Ex Output:
b


Ex Input:
Problem: if the length of the sides of two cubes are in the ratio 6: 1, what is the ratio of their total surface area ?
Options: a. 6: 1, b. 12: 1, c. 24: 1, d. 36: 1, e. 72: 1

Ex Output:

d