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 an article at rs . 1000 , a shopkeeper makes a profit of 25 % . at what price should he sell the article so as to make a loss of 25 % ? 
Options: a ) s . 600 , b ) s . 480 , c ) s . 500 , d ) s . 450 , e ) s . 550
Example Output: a

Example Input: Problem: a dishonest dealer professes to sell goods at the cost price but uses a weight of 990 grams per kg , what is his percent ? 
Options: a ) 1.01 % , b ) 25 % , c ) 22 % , d ) 29 % , e ) 45 %
Example Output: a

Example Input: Problem: a watch was sold at a loss of 20 % . if it was sold for rs . 520 more , there would have been a gain of 6 % . what is the cost price ? 
Options: a ) rs . 1500 , b ) rs . 2000 , c ) rs . 3000 , d ) rs . 4200 , e ) rs . 2500
Example Output:
b