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: there are 15 boys and 10 girls in a class. if three students are selected at random, in how many ways that 1 girl or 2 boys are selected ?
Options: a. 100, b. 105, c. 115, d. 120, e. 125

Ex Output:
c


Ex Input:
Problem: a store sells chairs and tables. if the price of 2 chairs and 1 table is 60 % of the price of 1 chair and 2 tables, and the price of 1 table and 1 chair is $ 64, what is the price, in dollars, of 1 table ? ( assume that every chair has the same price and every table has the same price. )
Options: a. 48, b. 52, c. 54, d. 58, e. 56

Ex Output:
e


Ex Input:
Problem: a person buys an article at rs. 400. at what price should he sell the article so as to make a profit of 40 % ?
Options: a. 600, b. 277, c. 560, d. 261, e. 281

Ex Output:

c