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 value of n if the sum of the consecutive odd intergers y from 1 to n equals 169 ?
Options: a. 47, b. 25, c. 37, d. 33, e. 29

Ex Output:
b


Ex Input:
Problem: the average of first 10 natural numbers is ?
Options: a. 5.6, b. 5.5, c. 5.1, d. 5.8, e. 5.2

Ex Output:
b


Ex Input:
Problem: john purchased 1375 large bottles at $ 1.75 per bottle and 690 small bottles at $ 1.35 per bottle. what was the approximate average price paid per bottle ?
Options: a. $ 1.62, b. $ 1.64, c. $ 1.68, d. $ 1.72, e. $ 1.76

Ex Output:

a