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 how many years will a sum of money doubles itself at 12 % per annum on simple interest ? 
Options: a ) 15 % , b ) 20 % , c ) 10 % , d ) 8 % , e ) 22 %
Example Output: d

Example Input: Problem: a man took loan from a bank at the rate of 12 % p . a . s . i . after 3 years he had to pay rs . 5400 interest only for the period . the principal amount borrowed by him was ? 
Options: a ) 15002 , b ) 15001 , c ) 15000 , d ) 15007 , e ) 15009
Example Output: c

Example Input: Problem: john makes $ 50 a week from his job . he earns a raise andnow makes $ 75 a week . what is the % increase ? 
Options: a ) 15 % , b ) 16.66 % , c ) 50 % , d ) 19 % , e ) 21 %
Example Output:
c