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: if difference between compound interest and simple interest on a sum at 10 % p . a . for 2 years is rs . 150 then sum is 
Options: a ) s . 15000 , b ) s . 15100 , c ) s . 15800 , d ) s . 16000 , e ) s . 16200
Example Output: a

Example Input: Problem: in an election between two candidates , one got 55 % of the total valid votes , 20 % of the votes were invalid . if the total number of votes was 6000 , the number of valid votes that the other candidate got , was : 
Options: a ) 2800 , b ) 2700 , c ) 2160 , d ) 2200 , e ) 2300
Example Output: c

Example Input: Problem: a man cheats while buying as well as while selling . while buying he takes 10 % more than what he pays for and while selling he gives 20 % less than what he claims to . find the profit percent , if he sells at 10 % below the cost price of the claimed weight . 
Options: a ) 19.81 % , b ) 20 % , c ) 37.5 % , d ) 23.75 % , e ) 37.5 %
Example Output:
d