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: a light flashes every 30 seconds, how many times will it flash in ? of an hour ?
Options: a. 550, b. 600, c. 650, d. 700, e. 120

Ex Output:
e


Ex Input:
Problem: if the average of 5 positive integers is 50 and the difference between the largest and the smallest of these 5 numbers is 10, what is the maximum value possible for the largest of these 5 integers ?
Options: a. 50, b. 58, c. 49, d. 48, e. 44

Ex Output:
b


Ex Input:
Problem: a car averages 30 miles per hour for the first 5 hours of a trip and averages 42 miles per hour for each additional hour of travel time. if the average speed for the entire trip is 38 miles per hour, how many hours long is the trip ?
Options: a. 13, b. 14, c. 15, d. 16, e. 17

Ex Output:

c