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: in how many years rs 160 will produce the same interest at 8 % as rs . 500 produce in 4 years at 8 % 
Options: a ) 13 , b ) 13.5 , c ) 11.5 , d ) 12.5 , e ) 12
Example Output: d

Example Input: Problem: in a certain parking lot , 2 % of the cars are towed for parking illegally . however 80 % of the cars which are parked illegally are not towed . what percentage of cars in the parking lot are parked illegally ? 
Options: a ) 4 % , b ) 6 % , c ) 8 % , d ) 10 % , e ) 12 %
Example Output: d

Example Input: Problem: a man bought an article and sold it at a gain of 5 % . if he had bought it at 5 % less and sold it for re 2 less , he would have made a profit of 10 % . the c . p . of the article was 
Options: a ) 344 , b ) 218 , c ) 400 , d ) 388 , e ) 211
Example Output:
c