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'.

Ex Input:
Problem: some of 10 % - intensity red paint is replaced with 20 % solution of red paint such that the new paint intensity is 15 % . what fraction of the original paint was replaced ? 
Options: a ) 2 / 5 , b ) 2 / 3 , c ) 1 / 2 , d ) 1 / 3 , e ) 1 / 5

Ex Output:
c


Ex Input:
Problem: one night 17 percent of the female officers on a police force were on duty . if 170 police officers were on duty that night and half of these were female officers , how many female officers were on the police force ? 
Options: a ) 400 , b ) 420 , c ) 450 , d ) 480 , e ) 500

Ex Output:
e


Ex Input:
Problem: if the cost price of 165 chocolates is equal to the selling price of 150 chocolates , the gain percent is 
Options: a ) 8 , b ) 9 , c ) 10 , d ) 11 , e ) 12

Ex Output:

c