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: a merchant sells an item at a 20 % discount, but still makes a gross profit of 20 percent of the cost. what percent of the cost would the gross profit on the item have been if it had been sold without the discount ?
Options: a. 20 %, b. 40 %, c. 50 %, d. 60 %, e. 75 %
Example Output: c

Example Input: Problem: when a certain number x is divided by 61, the remainder is 24. what is the remainder when x is divided by 5 ?
Options: a. 2, b. 3, c. 4, d. 5, e. 6
Example Output: c

Example Input: Problem: the mean proportional between 4 and 16 is ?
Options: a. 12, b. 13, c. 14, d. 15, e. 16
Example Output:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
e

