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: if y exceeds x by 25 %, then x is less than y by ?
Options: a. 28 %, b. 21 %, c. 20 %, d. 30 %, e. 29 %

Ex Output:
c


Ex Input:
Problem: i flew my tiny seaplane to visit my mother. on the flight up, i flew at 96 mph. on the way home, i flew 88 mph. what was my average speed for the trip ?
Options: a. 198 mph, b. 110 mph, c. 92 mph, d. 100 mph, e. 99 mph

Ex Output:
c


Ex Input:
Problem: a salesman ’ s terms were changed from a flat commission of 5 % on all his sales to a fixed salary of rs. 1000 plus 2.5 % commission on all sales exceeding rs. 4,000. if his remuneration as per new scheme was rs. 600 more than that by the previous schema, his sales were worth ?
Options: a. 12002, b. 12000, c. 12028, d. 12020, e. 12013

Ex Output:

b