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: by selling 10 pencils for a rupee a man loses 15 % . how many for a rupee should he sell in order to gain 15 % ? 
Options: a ) 8.39 , b ) 6.39 , c ) 7.39 , d ) 9.39 , e ) 2.39
Example Output: c

Example Input: Problem: if a large pizza has a radius that is 10 % larger that that of a medium pizza , what is the percent increase in area between a medium and a large pizza ? 
Options: a ) 15 % , b ) 21 % , c ) 25 % , d ) 30 % , e ) 36 %
Example Output: b

Example Input: Problem: how is 3 % expressed as a decimal fraction ? 
Options: a ) 0.3 , b ) 0.03 , c ) 0.003 , d ) 0.0003 , e ) 3
Example Output:
b