In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Ex Input:
Problem: 123 : 36 : : 221 : ? 
Options: a ) 52 , b ) 69 , c ) 72 , d ) 25 , e ) 32

Ex Output:
d


Ex Input:
Problem: the sum of the first 50 positive even integers is 2550 . what is the sum w of even integers from 102 to 200 inclusive ? 
Options: a ) 5100 , b ) 7550 , c ) 10100 , d ) 15500 , e ) 20100

Ex Output:
b


Ex Input:
Problem: if a certain computer is capable of printing 4700 monthly credit card bills per hour , while a new model is capable of printing at a rate of 6800 per hour , the old model will take approximately how much longer than the new model to print 10000 bills ? 
Options: a ) 19 mins , b ) 29 mins , c ) 39 mins , d ) 38 mins , e ) 37 mins

Ex Output:

c