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 rope of which a calf is tied is increased from 12 m to 23 m, how much additional grassy ground shall it graze ?
Options: a. 2989, b. 2789, c. 1210, d. 1288, e. 1211
[A]: c


[Q]: Problem: the purchase price of an article is $ 48. in order to include 5 % of cost for overhead and to provide $ 12 of net profit, the markup should be
Options: a. 15 %, b. 25 %, c. 30 %, d. 40 %, e. 45 %
[A]: c


[Q]: Problem: how many quarters are equal to 6 dollars ?
Options: a. 1, b. 8, c. 12, d. 9, e. 24
[A]:
e