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: he average of 10 numbers is 23. if each number is increased by 4, what will the new average be ?
Options: a. 26, b. 27, c. 88, d. 99, e. 12
Example Output: b

Example Input: Problem: the area of one square is x ^ 2 + 4 x + 4 and the area of another square is 4 x ^ 2 12 x + 9. if the sum of the perimeters of both squares is 32, what is the value of x ?
Options: a. 0, b. 2, c. 2.5, d. 4.67, e. 3
Example Output: e

Example Input: Problem: a student completes a 3 part exam as follows. the student completes sections a in 4 minutes and takes an equal time to complete the two remaining sections. what is the ratio of time spent on section c to section a if the total duration is 1 hour ?
Options: a. 10: 3, b. 9: 2, c. 7: 1, d. 8: 3, e. 11: 2
Example Output:
c