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: a van takes 5 hours to cover a distance of 495 km. what speed in kph should the van maintain to cover the same distance in 3 / 2 of the previous time ?
Options: a. 60, b. 63, c. 66, d. 69, e. 72

Output: c

Input: Consider Input: Problem: a cricketer whose bowling average is 12.4 runs per wicket takes 5 wickets for 26 runs and there by decreases his average by 0.4. the number age of the family now is :
Options: a. 18, b. 17, c. 76, d. 85, e. 86

Output: d

Input: Consider Input: Problem: if x: y is 1: 5 and y: z is 5: 7 then x: z is equal to
Options: a. 1: 6, b. 1: 5, c. 1: 4, d. 1: 7, e. 1: 3
Output: d