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: if 7 a - 3 b = 10 b + 50 = - 12 b - 2 a , what is the value of 9 a + 9 b ? 
Options: a ) - 9 , b ) - 6 , c ) 0 , d ) 6 , e ) 9

Ex Output:
c


Ex Input:
Problem: ( 18 ) 7 x ( 5832 ) - 2 ÷ ( 324 ) - 1 = ( 18 ) 7 
Options: a ) 5 , b ) 4 , c ) 3 , d ) 2 , e ) 1

Ex Output:
c


Ex Input:
Problem: when positive integer k is divided by 5 , the remainder is 2 . when k is divided by 6 , the remainder is 5 . if k is less than 38 , what is the remainder when k is divided by 7 ? 
Options: a ) 2 , b ) 4 , c ) 3 , d ) 5 , e ) 6

Ex Output:

c