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.

[Q]: Problem: list r contains 5 numbers that have an average value of 60. if the median of the numbers in the list is equal to the mean and the largest number is equal to 20 more than two times the smallest number, what is the smallest possible value in the list ?
Options: a. 25, b. 28, c. 31, d. 34, e. 37
[A]: b

[Q]: Problem: the speed of a boat in still water is 15 km / hr and the rate of current is 3 km / hr. the distance travelled downstream in 24 minutes is
Options: a. 17.2 km, b. 7.2 km, c. 7.6 km, d. 17.6 km, e. 27.2 km
[A]: b

[Q]: Problem: a store reported total sales of $ 416 million for february of this year. if the total sales for the same month last year was $ 320 million, approximately what was the percent increase in sales ?
Options: a. 2 %, b. 17 %, c. 30 %, d. 65 %, e. 83 %
[A]:
c