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: what is the rate percent when the simple interest on rs . 800 amount to rs . 200 in 4 years ? 
Options: a ) 5 % , b ) 7 % , c ) 6.25 % , d ) 2 % , e ) 4 %
Example Output: c

Example Input: Problem: the price of a book is increased from $ 300 to $ 480 . what is the % of increase in its price ? 
Options: a ) 10 % , b ) 20 % , c ) 40 % , d ) 50 % , e ) 60 %
Example Output: e

Example Input: Problem: i bought two books ; for rs . 480 . i sold one at a loss of 15 % and other at a loss of 25 % and then i found each book was sold at the same price . find the cost of the book sold at a lower loss ? 
Options: a ) a ) 657 , b ) b ) 280 , c ) c ) 225 , d ) d ) 289 , e ) e ) 427
Example Output:
c