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.

Input: Consider Input: Problem: what is the units digit of 32 ! + 50 ! + 4 ! + 4 ! ?
Options: a. 0, b. 2, c. 4, d. 6, e. 8

Output: e

Input: Consider Input: Problem: how many integers v are prime numbers in the range 200 < v < 220 ?
Options: a. 1, b. 2, c. 3, d. 4, e. 5

Output: a

Input: Consider Input: Problem: three pipes, a, b, & c are attached to a tank. a & b can fill it in 20 & 30 minutes respectively while c can empty it in 20 minutes. if a, b & c are kept open successively for 1.5 minute each, how soon will the tank be filled ?
Options: a. 2 hours, b. 4 hours, c. 5 hours, d. 2 hours 15 min, e. 3 hours
Output: d