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: the product of a and b is equal to 12 more than twice the sum of a and b . if b = 10 , what is the value of b - a ? 
Options: a ) 2 , b ) 5 , c ) 7 , d ) 6 , e ) 35
Example Output: d

Example Input: Problem: find out the square of a number which when doubled exceeds its one fifth by 9 ? 
Options: a ) 16 , b ) 25 , c ) 19 , d ) 26 , e ) 17
Example Output: b

Example Input: Problem: what is the units digit of ( 5 ! * 4 ! + 6 ! * 5 ! ) / 2 ? 
Options: a ) 4 , b ) 3 , c ) 0 , d ) 1 , e ) 2
Example Output:
c