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.
--------
Question: Problem: buses a and b start from a common bus stop x. bus a begins to travel in a straight line away from bus b at a constant rate of 20 miles per hour. one hour later, bus b begins to travel in a straight line in the exact opposite direction at a constant rate of 80 miles per hour. if both buses travel indefinitely, what is the positive difference, in minutes, between the amount of time it takes bus b to cover the exact distance that bus a has covered and the amount of time it takes bus b to cover twice the distance that bus a has covered ?
Options: a. 36, b. 72, c. 132, d. 144, e. 180

Answer: c

Question: Problem: bottle r contains 350 capsules and costs $ 6.25. bottle t contains 130 capsules and costs $ 2.99. what is the difference between the cost per capsule for bottle r and the cost per capsule for bottle t ?
Options: a. $ 0.25, b. $ 0.12, c. $ 0.0052, d. $ 0.003, e. $ 0.002

Answer: c

Question: Problem: the average runs scored by a batsman in 25 matches is 45. in the next 7 matches the batsman scored an average of 15 runs. find his average in all the 32 matches ?
Options: a. 31355, b. 38.44, c. 29.55, d. 97.66, e. 45.66

Answer:
b