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: two guys a and b leave point a and point b simultaneously and travel towards point b and point a on the same route at their respective constant speeds. they meet along the route and immediately proceed to their respective destinations in 32 minutes and 50 minutes respectively. how long will b take to cover the entire journey between point b and point a ?
Options: a. 65, b. 90, c. 70, d. 75, e. 80

Ex Output:
b

Ex Input:
Problem: mary works in a restaurant a maximum of 70 hours. for the first 20 hours, she is paid $ 8 per hour. for each overtime hour, she is paid at a rate which is 25 % higher than her regular rate. how much mary can earn in a week ?
Options: a. 600, b. 620, c. 660, d. 320, e. 400

Ex Output:
c

Ex Input:
Problem: what is the lowest positive integer that is divisible by each of the integers 1 through 12 inclusive ?
Options: a. 420, b. 840, c. 1260, d. 2520, e. 27,720

Ex Output:
e