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: some of 10 % - intensity red paint is replaced with 20 % solution of red paint such that the new paint intensity is 15 % . what fraction of the original paint was replaced ? 
Options: a ) 2 / 5 , b ) 2 / 3 , c ) 1 / 2 , d ) 1 / 3 , e ) 1 / 5
Example Output: c

Example Input: Problem: a shopkeeper loses 15 % , if an article is sold for rs . 136 . what should be the selling price of the article to gain 20 % ? 
Options: a ) s . 147 , b ) s . 148 , c ) s . 144 , d ) s . 189 , e ) s . 192
Example Output: e

Example Input: Problem: a fair price shopkeeper takes 10 % profit on his goods . he lost 20 % goods during theft . his loss percent is : 
Options: a ) 10 , b ) 13 , c ) 12 , d ) 18 , e ) 19
Example Output:
c