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'.

Example Input: Problem: a is two years older than b who is twice as old as c . if the total of the ages of a , b and c be 12 , the how old is b ?
Options: a ) 10 years , b ) 4 years , c ) 6 years , d ) 15 years , e ) 16 years
Example Output: b

Example Input: Problem: for the positive integers x , x + 2 , x + 4 , x + 7 , and x + 17 , the mean is how much greater than the median ?
Options: a ) 0 , b ) 1 , c ) 2 , d ) 4 , e ) 7
Example Output: c

Example Input: Problem: there are 10 teams in a certain league and each team plays each of the other teams exactly once . what is the total number of games played ?
Options: a ) 30 , b ) 36 , c ) 42 , d ) 45 , e ) 50
Example Output:
d