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 a man lost 10 % by selling oranges at the rate of 12 a rupee at how many a rupee must he sell them to gain 44 % ?
Options: a. 6.5, b. 7.5, c. 7, d. 8, e. 2

Ex Output:
b


Ex Input:
Problem: in what time will a train 120 m long cross an electric pole, it its speed be 121 km / hr ?
Options: a. 2.5, b. 2.7, c. 2.9, d. 3.6, e. 2.1

Ex Output:
d


Ex Input:
Problem: the product z of two prime numbers is between 16 and 40. if one of the prime numbers is greater than 2 but less than 6 and the other is greater than 12 but less than 30 then what is z ?
Options: a. 21, b. 22, c. 28, d. 35, e. 39

Ex Output:

e