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: mr . karan borrowed a certain amount at 6 % per annum simple interest for 9 years . after 9 years , he returned rs . 8310 / - . find out the amount that he borrowed . 
Options: a ) s . 5266 , b ) s . 5396 , c ) s . 5228 , d ) s . 5218 , e ) s . 52192
Example Output: b

Example Input: Problem: at a particular graduation party with 300 guests , 70 % of the guests brought gifts , and 40 % of the female guests brought gifts . if 15 males did not bring gifts to the party , how many females did bring gifts ? 
Options: a ) 18 , b ) 28 , c ) 50 , d ) 68 , e ) 70
Example Output: c

Example Input: Problem: a present value of a machine is $ 1200 . its value depletion rate is 10 % per annum then find the machine value after 2 years ? 
Options: a ) $ 972 , b ) $ 810 , c ) $ 915 , d ) $ 715 , e ) $ 795
Example Output:
a