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: students at a school were on average 180 cm tall. the average female height was 170 cm, and the average male height was 182 cms. what was the ratio of men to women ?
Options: a. 5: 2, b. 5: 1, c. 4: 3, d. 4: 1, e. 3: 1
Example Output: b

Example Input: Problem: solution y is 30 percent liquid x and 70 percent water. if 2 kilograms of water evaporate from 6 kilograms of solution y and 2 kilograms of solution y are added to the remaining 4 kilograms of liquid, what percent of this new solution is liquid x ?
Options: a. 33 %, b. 35 1 / 2 %, c. 37 %, d. 40 %, e. 42 %
Example Output: d

Example Input: Problem: a grocery store bought some mangoes at a rate of 5 for a dollar. they were separated into two stacks, one of which was sold at a rate of 3 for a dollar and the other at a rate of for a dollar. what was the ratio of the number of mangoes in the two stacks if the store broke even after having sold all of its mangoes ?
Options: a. 1: 4, b. 16: 9, c. 2: 3, d. 1: 2, e. 2: 5
Example Output:
b