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'.

Ex 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

Ex Output:
e

Ex Input:
Problem: what profit percent is made by selling an article at a certain price , if by selling at 1 / 2 rd of that price , there would be a loss of 20 % ?
Options: a ) 20 % , b ) 29 % , c ) 60 % , d ) 27 % , e ) 28 %

Ex Output:
c

Ex Input:
Problem: in a certain pond , 60 fish were caught , tagged , and returned to the pond . a few days later , 60 fish were caught again , of which 2 were found to have been tagged . if the percent of tagged fish in the second catch approximates the percent of tagged fish in the pond , what ' s the approximate number of fish in the pond ?
Options: a ) 400 , b ) 625 , c ) 1818 , d ) 2500 , e ) 10 000

Ex Output:
c