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 - 3 x + 2 y = 28 and 3 x + 6 y = 84 , what is the product of x and y ? 
Options: a ) 264 . , b ) 428 , c ) 0 , d ) 462 , e ) 642

Ex Output:
c


Ex Input:
Problem: ages of two persons differ by 20 years . if 6 year ago , the elder one be 3 times as old the younger one , find their present age 
Options: a ) 12,28 , b ) 14,30 , c ) 16,36 , d ) 18,34 , e ) 19,34

Ex Output:
c


Ex Input:
Problem: ( 9 ^ 5.6 x 9 ^ 10.3 ) ÷ 9 ^ 2.56256 = 9 ^ ? 
Options: a ) 11.34 , b ) 12.34 , c ) 13.34 , d ) 14.34 , e ) 15.34

Ex Output:

c