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: if the cost price of 50 articles is equal to the selling price of 20 articles , then the gain or loss percent is ? 
Options: a ) 16 , b ) 127 , c ) 12 , d ) 18 , e ) 150
Example Output: e

Example Input: Problem: at what rate percent per annum will the simple interest on a sum of money be 4 / 5 of the amount in 10 years ? 
Options: a ) 4 % , b ) 7 % , c ) 8 % , d ) 3 % , e ) 1 %
Example Output: c

Example Input: Problem: a man buys a cycle for rs . 800 and sells it at a loss of 15 % . what is the selling price of the cycle ? 
Options: a ) s . 1090 , b ) s . 1160 , c ) s . 680 , d ) s . 520 , e ) s . 700
Example Output:
c