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: the probability of two events a and b are 0.25 and 0.40 respectively. the probability that both a and b occur is 0.15. the probability that neither a nor b occur is _________
Options: a. 0.45, b. 0.4, c. 0.5, d. 0.05, e. 0.6
Example Output: c

Example Input: Problem: the dimensions of a room are 25 feet * 15 feet * 12 feet. what is the cost of white washing the four walls of the room at rs. 10 per square feet if there is one door of dimensions 6 feet * 3 feet and three windows of dimensions 4 feet * 3 feet each ?
Options: a. s. 9060, b. s. 4520, c. s. 4527, d. s. 4530, e. s. 4521
Example Output: a

Example Input: Problem: if m is a positive integer and m ^ 2 is divisible by 24, then the largest positive integer that must divide m is ?
Options: a. 3, b. 6, c. 8, d. 12, e. 16
Example Output:
c