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: vehicle x is 22 miles ahead of vehicle y, which is traveling the same direction along the same route as vehicle x. if vehicle x is traveling at an average speed of 36 miles per hour and vehicle y is traveling at an average speed of 45 miles per hour, how long will it take vehicle y to overtake and drive 23 miles ahead of vehicle x ?
Options: a. 5 hours, b. 7 hours 20 minutes, c. 4 hours, d. 3 hours 45 minutes, e. 2 hours 30 minutes

Output: a

Input: Consider Input: Problem: in n is a positive integer less than 200, and 14 n / 60 is an integer, then n has how many different positive prime factors s ?
Options: a. 2, b. 3, c. 5, d. 6, e. 8

Output: b

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