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 fruit seller had some oranges . he sells 30 % oranges and still has 420 oranges . how many oranges he had originally ? 
Options: a ) 420 , b ) 600 , c ) 220 , d ) 400 , e ) none of these
Example Output: b

Example Input: Problem: on selling 17 balls at rs . 720 , there is a loss equal to the cost price of 5 balls . the cost price of a ball is 
Options: a ) 20 , b ) 30 , c ) 40 , d ) 50 , e ) 60
Example Output: e

Example Input: Problem: how much 60 % of 50 is greater than 30 % of 30 ? 
Options: a ) 21 , b ) 91 , c ) 11 , d ) 17 , e ) 12
Example Output:
a