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: a lent rs . 5000 to b for 2 years and rs . 3000 to c for 4 years on simple interest at the same rate of interest and received rs . 1760 in all from both of them as interest . the rate of interest per annum is ? 
Options: a ) 16 % , b ) 12 % , c ) 74 % , d ) 10 % , e ) 8 %
Example Output: 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: if 40 % of a certain number is 160 , then what is 20 % of that number ? 
Options: a ) 75 , b ) 100 , c ) 120 , d ) 30 , e ) 80
Example Output:
e