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: 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: the interest on a certain deposit at 4.5 % p . a . is rs . 405 in one year . how much will the additional interest in one year be on the same deposit at 5 % p . a . ? 
Options: a ) rs . 50 , b ) rs . 45 , c ) rs . 40.5 , d ) rs . 48.5 , e ) rs . 49.5
Example Output: b

Example Input: Problem: a reduction in the price of petrol by 10 % enables a motorist to buy 5 gallons more for $ 250 . find the original price of petrol ? 
Options: a ) $ 11 , b ) $ 5 , c ) $ 45 , d ) $ 400 , e ) $ 5.5
Example Output:
e