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.

Input: Consider 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 %

Output: c


Input: Consider Input: Problem: dropbox charges $ 3.10 for first 1 / 5 of a month for 500 gb storage, plus $ 0.40 for each additional 1 / 5 of a month. what would dropbox charge for a data storage of 500 gb for 8 months ?
Options: a. $ 15.60, b. $ 16.00, c. $ 17.80, d. $ 18.70, e. $ 19.10

Output: d


Input: Consider Input: Problem: a man sitting in a train which is travelling at 50 kmph observes that a goods train, travelling in opposite direction, takes 9 seconds to pass him. if the goods train is 280 m long, find its speed ?
Options: a. 52 kmph., b. 62 kmph., c. 72 kmph., d. 80 kmph., e. none


Output: b