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: what is the smallest integer that is multiple of 5, 711
Options: a. a. 70, b. b. 35, c. c. 385, d. d. 280, e. e. 140

Ex Output:
c


Ex Input:
Problem: in what ratio must a grocer mix two varieties of pulses costing rs. 15 and rs. 20 per kg respectively so as to get a mixture worth rs. 16.50 per kg ?
Options: a. 3: 7, b. 5: 7, c. 7: 3, d. 7: 5, e. none

Ex Output:
c


Ex Input:
Problem: if the average of 16 x and 8 y is greater than 80, and x is twice y, what is the least integer value of x ?
Options: a. 8, b. 9, c. 10, d. 11, e. 12

Ex Output:

a