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: excluding the stoppages, the speed of a bus is 48 km / hr and including the stoppages the speed of the bus is 12 km / hr. for how many minutes does the bus stop per hour ?
Options: a. 45 min, b. 10 min, c. 12 min, d. 20 min, e. 18 min

Answer: a


Question: Problem: if a randomly selected positive single digit multiple of 3 is multiplied by a randomly selected prime number less than 20, what is the probability w that this product will be a multiple of 45 ?
Options: a. 1 / 32, b. 1 / 28, c. 1 / 24, d. 1 / 16, e. 1 / 14

Answer: c


Question: Problem: ( 3080 + 6160 ) / 28
Options: a. 380, b. 350, c. 330, d. 310, e. none of these

Answer:
c