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: the h. c. f. of two numbers is 30 and the other two factors of their l. c. m. are 15 and 12. the larger of the two numbers is
Options: a. 476, b. 399, c. 450, d. 322, e. none

Output: c


Input: Consider Input: Problem: the speed of the boat in still water in 12 kmph. it can travel downstream through 48 kms in 3 hrs. in what time would it cover the same distance upstream ?
Options: a. 8 hours, b. 6 hours, c. 4 hours, d. 5 hours, e. 6 hours

Output: e


Input: Consider Input: Problem: a mail handler needs 3 hours to sort the mail. his assistant takes 6 hours to sort the mail. how many hours will it take for both of them working together to sort the mail ?
Options: a. 3, b. 2, c. 1, d. 2 1 / 2, e. 1 1 / 5


Output: b