Definition: 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.
Input: Problem: a man sells a car to his friend at 10 % loss. if the friend sells it for rs. 54000 and gains 20 %, the original c. p. of the car was :
Options: a. rs. 25000, b. rs. 37500, c. rs. 50000, d. rs. 60000, e. none of these
Output:
c