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: the c . p of 20 books is equal to the s . p of 30 books . find his gain % or loss % ?
Options: a ) 63.33 % , b ) 34.33 % , c ) 33.33 % , d ) 31.33 % , e ) 36.33 %
Example Output: c

Example Input: Problem: a , b and c invests rs . 2000 , rs . 3000 and rs . 4000 in a business . after one year a removed his money ; b and c continued the business for one more year . if the net profit after 2 years be rs . 3200 , then a ' s share in the profit is ?
Options: a ) 299 , b ) 267 , c ) 269 , d ) 400 , e ) 276
Example Output: d

Example Input: Problem: the compound interest earned on a sum for the second and the third years are $ 1400 and $ 1540 respectively . what is the rate of interest ?
Options: a ) 2 % , b ) 4 % , c ) 6 % , d ) 8 % , e ) 10 %
Example Output:
e