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: evaluate : 28 % of 400 + 45 % of 250 
Options: a ) 220.3 , b ) 224.5 , c ) 190.3 , d ) 150 , e ) none of these

Ex Output:
b


Ex Input:
Problem: the simple interest on rs . 20 for 6 months at the rate of 5 paise per rupeeper month is 
Options: a ) 1.2 , b ) 1.4 , c ) 6 , d ) 7 , e ) none

Ex Output:
c


Ex Input:
Problem: if 15 % of a class averages 100 % on a test , 50 % of the class averages 78 % on the test , and the remainder of the class averages 63 % on the test , what is the overall class average ? ( round final answer to the nearest percent ) . 
Options: a ) 76 % , b ) 77 % , c ) 78 % , d ) 79 % , e ) 80 %

Ex Output:

a