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: ravi purchased a refrigerator and a mobile phone for rs. 15000 and rs. 8000 respectively. he sold the refrigerator at a loss of 5 percent and the mobile phone at a profit of 10 percent. overall he make a.
Options: a. 50, b. 288, c. 27, d. 200, e. 881

Ex Output:
a

Ex Input:
Problem: in n is a positive integer less than 200, and 14 n / 60 is an integer, then n has how many different positive prime factors s ?
Options: a. 2, b. 3, c. 5, d. 6, e. 8

Ex Output:
b

Ex Input:
Problem: a school has 4 section of chemistry in class x having 40, 35, 45 and 42 students. the mean marks obtained in chemistry test are 50, 60, 55 and 45 respectively for the 4 sections. determine the overall average of marks per student.
Options: a. 50.25, b. 52.25, c. 51.25, d. 53.25, e. none of the above

Ex Output:
b