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 c . p of 20 books is equal to the s . p of 30 books . find his gain % or loss % ? 
Options: a ) 63.33 % , b ) 34.33 % , c ) 33.33 % , d ) 31.33 % , e ) 36.33 %
Example Output: c

Example Input: Problem: a shopkeeper loses 15 % , if an article is sold for rs . 136 . what should be the selling price of the article to gain 20 % ? 
Options: a ) s . 147 , b ) s . 148 , c ) s . 144 , d ) s . 189 , e ) s . 192
Example Output: e

Example Input: Problem: what annual installment will discharge a debt of rs . 1344 due in 3 years at 12 % simple interest ? 
Options: a ) 315 , b ) 345 , c ) 325 , d ) 335 , e ) 400
Example Output:
e