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 , b and c invested rs . 8000 , rs . 4000 and rs . 8000 respectively in a business . a left after six months . if after eight months , there was a gain of rs . 4005 , then what will be the share of b ? 
Options: a ) rs 690 , b ) rs 790 , c ) rs 890 , d ) rs 990 , e ) none of these
Example Output: c

Example Input: Problem: what is the rate percent when the simple interest on rs . 4000 amount to rs . 320 in 2 years ? 
Options: a ) 4 % , b ) 4.1 % , c ) 4.2 % , d ) 4.3 % , e ) 4.5 %
Example Output: a

Example Input: Problem: a man sells a car to his friend at 15 % loss . if the friend sells it for rs . 54000 and gains 20 % , the original c . p . of the car was : 
Options: a ) rs . 22941.18 , b ) rs . 32941.18 , c ) rs . 52941.18 , d ) rs . 62941.18 , e ) none of these
Example Output:
c