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: if 80 percent of a class answered the first question on a certain test correctly, 55 percent answered the second question on the test correctly, and 20 percent answered neither of the questions correctly, what percent answered both correctly ?
Options: a. 10 %, b. ( 8 ) 20 %, c. 30 %, d. 50 %, e. 55 %

Ex Output:
e

Ex Input:
Problem: the salary of a person was reduced by 14 %. by what percent should his reduced salary be raised so as to bring it at par with his original salary ?
Options: a. 10 %, b. 16.3 %, c. 13.7 %, d. 15.1 %, e. 12.3 %

Ex Output:
b

Ex Input:
Problem: the age of somu is one - third his father ' s. 8 years back he was one - fifth of his father ' s age. what is his persent age ?
Options: a. 11, b. 13, c. 14, d. 16, e. 10

Ex Output:
d