In this task, you need to answer the given multiple-choice question on the gain. Gain is the value by which to multiply the input. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Example Input: Problem: the true discount on a bill of rs . 2660 is rs . 360 . what is the banker ' s discount ? 
Options: a ) rs . 432 , b ) rs . 422 , c ) rs . 416 , d ) rs . 442 , e ) none of these
Example Output: c

Example Input: Problem: solve the quickfire maths brain teaser â ˆ š 25 % = ? 
Options: a ) 30 % , b ) 40 % , c ) 50 % , d ) 19 % , e ) 29 %
Example Output: c

Example Input: Problem: a man buys an article for $ 20 . and sells it for $ 25 . find the gain percent ? 
Options: a ) 25 % , b ) 50 % , c ) 20 % , d ) 15 % , e ) 30 %
Example Output:
a