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: exactly 35 % of the reporters for a certain wire service cover local politics in country x. if 30 % of the reporters who cover politics for the wire service do not cover local politics in country x, what percent of the reporters for the wire service do not cover politics ?
Options: a. 20 %, b. 42 %, c. 44 %, d. 50 %, e. 84 %

Ex Output:
d


Ex Input:
Problem: a certain library assesses fines for overdue books as follows. on the first day that a book is overdue, the total fine is $ 0.09. for each additional day that the book is overdue, the total fine is either increased by $ 0.30 or doubled, whichever results in the lesser amount. what is the total for a book on the fourth day it is overdue ?
Options: a. $ 0.66, b. $ 0.70, c. $ 0.80, d. $ 0.90, e. $ 1.00

Ex Output:
a


Ex Input:
Problem: the diagonal of a cube is 8 √ 3. find its volume and surface area.
Options: ['a. 354', 'b. 384', 'c. 324', 'd. 344', 'e. 364']

Ex Output:

b