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 simple interest on a certain sum of money for 2 years at 10 % per annum is half the compound interest on $ 100 for 2 years at 5 % per annum . the sum placed on simple interest is ? 
Options: a ) $ 602.5 , b ) $ 625.8 , c ) $ 710.6 , d ) $ 745 , e ) $ 790.3
Example Output: a

Example Input: Problem: how much 60 % of 50 is greater than 30 % of 30 ? 
Options: a ) 21 , b ) 91 , c ) 11 , d ) 17 , e ) 12
Example Output: a

Example Input: Problem: raman mixed 48 kg of butter at rs . 150 per kg with 36 kg butter at the rate of rs . 125 per kg . at what price per kg should he sell the mixture to make a profit of 40 % in the transaction ? 
Options: a ) 129 , b ) 287 , c ) 195 , d ) 188 , e ) 112
Example Output:
c