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.

[EX Q]: Problem: if a man lost 8 % by selling oranges at the rate of 25 a rupee at how many a rupee must he sell them to gain 25 % ?
Options: a. 20, b. 15, c. 18.4, d. 20, e. 12.8
[EX A]: c

[EX Q]: Problem: a cyclist bikes x distance at 8 miles per hour and returns over the same path at 10 miles per hour. what is the cyclist ' s average rate for the round trip in miles per hour ?
Options: a. 8.1, b. 8.9, c. 8.6, d. 8.3, e. 9.0
[EX A]: b

[EX Q]: Problem: a rectangular block 15 cm by 30 cm by 75 cm is cut into an exact number of equal cubes. find the least possible number of cubes ?
Options: ['a. 6', 'b. 40', 'c. 15', 'd. 10', 'e. 22']
[EX A]:
d

