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: a grocer has a sale of rs. 5420, rs. 5660, rs. 6200, rs. 6350 and rs. 6500 for 5 consecutive months. find the sale he should have in the sixth month, so that he gets an average sale of rs. 6400 ?
Options: a. rs. 5870, b. rs. 8270, c. rs. 6020, d. rs. 6850, e. none of these
[A]: b

[Q]: Problem: a fort had provision of food for 150 men for 45 days. after 10 days, 25 men left the fort. find out the number of days for which the remaining food will last.
Options: a. 44, b. 42, c. 40, d. 38, e. 36
[A]: b

[Q]: Problem: during a certain two - week period, 60 percent of the movies rented from a video store were comedies, and of the remaining movies rented, there were 3 times as many dramas as action movies. if no other movies were rented during that two - week period and there were a action movies rented, then how many comedies, in terms of a, were rented during that two - week period ?
Options: a. 5 a, b. 6 a, c. 8 a, d. 14 a, e. 20 a
[A]:
b