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 milk man has 15 liters of milk . if he mixes 5 liters of water , which is freely available , in 20 liters of pure milk . if the cost of pure milk is rs . 18 per liter , then the profit of the milkman , when he sells all the mixture at cost price is : 
Options: a ) 20 % , b ) 25 % , c ) 33.33 % , d ) 18 % , e ) none of these
Example Output: a

Example Input: Problem: yesterday ' s closing prices of 1,980 different stocks listed on a certain stock exchange were all different from today ' s closing prices . the number of stocks that closed at a higher price today than yesterday was 20 percent greater than the number that closed at a lower price . how many of the stocks closed at a higher price today than yesterday ? 
Options: a ) 484 , b ) 1080 , c ) 1,100 , d ) 1,320 , e ) 1,694
Example Output: b

Example Input: Problem: a fruit seller had some apples . he sells 50 % apples and still he has 5000 . originally he had how many apples ? 
Options: a ) 10000 , b ) 15200 , c ) 11005 , d ) 12540 , e ) 12450
Example Output:
a