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.

Ex Input:
Problem: kim has 3 pairs of shoes; each pair is a different color. if kim randomly selects 2 shoes without replacement from the 6 shoes, what is the probability that she will select 2 shoes of the same color ?
Options: a. 2 / 5, b. 1 / 5, c. 1 / 9, d. 1 / 10, e. 1 / 25

Ex Output:
b


Ex Input:
Problem: an engine moves at the speed of 30 kmph without any coaches attached to it. speed of the train reduces at the rate that varies directly as the square root of the number of coaches attached. when 9 coaches are attached speed decreases to 18 kmph. what will be the speed of train when 16 coaches are attached.
Options: a. 14, b. 16, c. 18, d. 20, e. 22

Ex Output:
a


Ex Input:
Problem: an employee ’ s annual salary was increased $ 5000. if her new annual salary now equals $ 25000 what was the percent increase ?
Options: a. 15 %, b. 80 %, c. 20 %, d. 22 %, e. 24 %

Ex Output:

b