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: the banker ' s gain of a certain sum due 2 years hence at 10 % per annum is rs . 24 . the present worth is : 
Options: a ) rs . 608 , b ) rs . 6076 , c ) rs . 600 , d ) rs . 602 , e ) rs . 601
Example Output: c

Example Input: Problem: the cost price of an article is 70 % of the marked price . calculate the gain percent after allowing a discount of 10 % . 
Options: a ) 13.6 % , b ) 28.6 % , c ) 35.6 % , d ) 42.3 % , e ) none
Example Output: b

Example Input: Problem: a person buys an article at rs . 500 . at what price should he sell the article so as to make a profit of 20 % ? 
Options: a ) 600 , b ) 2877 , c ) 208 , d ) 1882 , e ) 191
Example Output:
a