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: mrs. evans gave a test to her freshmen economics class, which has 29 students enrolled and 19 of them answered question 1 correctly. if 24 answered question 2 correctly and 5 did not take the test then how many answered both questions correctly ?
Options: a. 3, b. 9, c. 11, d. 17, e. 19
Example Output: e

Example Input: Problem: a and b started a business investing rs. 80,000 and rs 20,000 respectively. in what ratio the profit earned after 2 years be divided between a and b respectively ?
Options: a. 4: 1, b. 3: 2, c. 18: 20, d. 18: 4, e. 17: 4
Example Output: a

Example Input: Problem: what is the smallest integer k for which 64 ^ k > 4 ^ 20 ?
Options: a. 4, b. 5, c. 6, d. 7, e. 8
Example Output:
d