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: a gardener grows cabbages in her garden that is in the shape of a square. each cabbage takes 1 square feet of area in her garden. this year, she has increased her output by 193 cabbages as compared to last year. the shape of the area used for growing the cabbages has remained a square in both these years. how many cabbages did she produce this year ?
Options: a. 8,208, b. 9,409, c. 11,424, d. 12,586, e. can not be determined
[EX A]: b

[EX Q]: Problem: buses a and b start from a common bus stop x. bus a begins to travel in a straight line away from bus b at a constant rate of 20 miles per hour. one hour later, bus b begins to travel in a straight line in the exact opposite direction at a constant rate of 80 miles per hour. if both buses travel indefinitely, what is the positive difference, in minutes, between the amount of time it takes bus b to cover the exact distance that bus a has covered and the amount of time it takes bus b to cover twice the distance that bus a has covered ?
Options: a. 36, b. 72, c. 132, d. 144, e. 180
[EX A]: c

[EX Q]: Problem: sam and nik start from a and b respectively at the same time and travel towards each other at constant speeds along the same route. sam meets nik at point c on the road which is 600 m away from starting point a and 400 m away from point b. the speed of sam is 50 m / m ( meter / minute.. how much time did sam take to cover the distance between a and b ?
Options: a. 10 minutes, b. 15 minutes, c. 20 minutes, d. 22 minutes, e. 17 minutes
[EX A]:
c