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: the sum of all the integers k such that – 25 < k < 24 is 
Options: a ) 0 , b ) - 2 , c ) - 25 , d ) - 49 , e ) - 47

Ex Output:
e


Ex Input:
Problem: if 4 xz + yw = 3 and xw + yz = 6 , what is the value of the expression ( 2 x + y ) ( 2 z + w ) ? 
Options: a ) 9 . , b ) 12 . , c ) 15 . , d ) 16 , e ) 18 .

Ex Output:
c


Ex Input:
Problem: there are 7 teams in a certain league and each team plays each of the other teams exactly twice . if each game is played by 2 teams , what is the total number of games played ? 
Options: a ) 15 , b ) 16 , c ) 28 , d ) 42 , e ) 64

Ex Output:

d