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.
--------
Question: Problem: if n is a positive integer and n ^ 2 is divisible by 36, then the largest positive integer that must divide n is
Options: a. 6, b. 12, c. 24, d. 36, e. 48

Answer: a

Question: Problem: if the radius of a cylinder is made 3 times and so is the height, what is the new volume of the cylinder divided by the old one ?
Options: a. 27., b. 2., c. 6., d. 4., e. 10.

Answer: a

Question: Problem: the true discount on a bill of rs. 2260 is rs. 360. what is the banker ' s discount ?
Options: a. rs. 428, b. rs. 422, c. rs. 412, d. rs. 442, e. none of these

Answer:
a