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'.

Input: Consider Input: Problem: how many halves are there in 9 - fourth ? 
Options: a ) 8 , b ) 4.5 , c ) 3.2 , d ) 7 , e ) 3

Output: b


Input: Consider Input: Problem: a ’ s speed is 20 / 19 times that of b . if a and b run a race , what part of the length of the race should a give b as a head start , so that the race ends in a dead heat ? 
Options: a ) 1 / 19 , b ) 3 / 19 , c ) 1 / 10 , d ) 1 / 20 , e ) 3 / 10

Output: d


Input: Consider Input: Problem: if n is an integer , f ( n ) = f ( n - 1 ) - n and f ( 4 ) = 12 . what is the value of f ( 6 ) ? 
Options: a ) 1 , b ) 0 , c ) - 1 , d ) 2 , e ) 4


Output: a