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: ifaequals the sum of the even integers from 2 to 20 , inclusive , andbequals the sum of the odd integers from 1 to 19 , inclusive , what is the value of b - a ? 
Options: a ) - 10 , b ) 10 , c ) - 19 , d ) 20 , e ) 21

Ex Output:
a


Ex Input:
Problem: set s contains exactly 10 numbers and has an average ( arithmetic mean ) of 6.2 . if one of the numbers in set s is increased by 8 , while all other numbers remain the same , what is the new average of set s ? 
Options: a ) 6.6 , b ) 6.7 , c ) 6.8 , d ) 7.0 , e ) 6.9

Ex Output:
d


Ex Input:
Problem: how many even multiples of 55 are there between 549 and 1101 ? 
Options: a ) 5 , b ) 6 , c ) 9 , d ) 10 , e ) 11

Ex Output:

b