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.

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
c

Problem: p has $ 32 more than what q and r together would have had if both b and c had 1 / 6 of what p has. how much does p have ?
Options: a. $ 44, b. $ 48, c. $ 52, d. $ 56, e. $ 60
b

Problem: in one hour, a boat goes 7 km along the steram and 5 km against the stream. the speed of the boat in still waer ( in km / hr ) is :
Options: a. 2, b. 4, c. 6, d. 12, e. 15
c