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.

Example Input: Problem: what is the rate percent when the simple interest on rs. 810 amount to rs. 155 in 4 years ?
Options: a. 4.78, b. 4.68, c. 4.58, d. 4.48, e. 4.38
Example Output: a

Example 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
Example Output: e

Example Input: Problem: a paint store mixes 3 / 4 pint of red paint and 2 / 3 pint of white paint to make a new paint color called perfect pink. how many pints of red paint would be needed to make 33 pints of perfect pink paint ?
Options: a. 9, b. 16, c. 17, d. 25 1 / 3, e. 28 1 / 2
Example Output:
c