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 20 liters of milk . if he mixes 25 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 ) 45 % , c ) 33.33 % , d ) 18 % , e ) none of these
Example Output: b

Example Input: Problem: p and q invested in a shop . the profits were divided in the ratio of 5 : 2 respectively . if p invested rs . 5600 , the amount invested by q is : 
Options: a ) 3500 , b ) 5600 , c ) 2200 , d ) 2400 , e ) none
Example Output: e

Example Input: Problem: john purchased a grinder and a mobile for rs . 15000 & rs . 10000 respectively . he sold the grinder at a loss of 4 % and the mobile phone at a profit of 10 % . overall how much he make a profit . 
Options: a ) s . 400 , b ) s . 120 , c ) s . 420 , d ) s . 450 , e ) s . 290
Example Output:
a