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'.

Input: Consider Input: Problem: how many liters of water must be evaporated from 50 liters of a 2 - percent sugar solution to get a 10 - percent solution ? 
Options: a ) 25 , b ) 30 , c ) 35 , d ) 40 , e ) 45

Output: d


Input: Consider Input: Problem: if 15 % of 40 is greater than 25 % of a number by 2 , the number is 
Options: a ) 14 , b ) 16 , c ) 18 , d ) 20 , e ) 22

Output: b


Input: Consider Input: Problem: the ratio of investments of two partners p and q is 7 : 5 and the ratio of their profits is 7 : 13 . if p invested the money for 5 months , find for how much time did q invest the money ? 
Options: a ) 19 , b ) 17 , c ) 13 , d ) 10 , e ) 12


Output: c