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 n is an integer , f ( n ) = f ( n - 1 ) - n and f ( 4 ) = 14 . what is the value of f ( 6 ) ? 
Options: a ) 3 , b ) 0 , c ) 1 , d ) 2 , e ) 4

Ex Output:
a


Ex Input:
Problem: how many numbers from 19 to 79 are exactly divisible by 11 ? 
Options: a ) 5 , b ) 6 , c ) 9 , d ) 11 , e ) 12

Ex Output:
b


Ex Input:
Problem: a type of extra - large suv averages 12.2 miles per gallon ( mpg ) on the highway , but only 7.6 mpg in the city . what is the maximum distance , in miles , that this suv could be driven on 21 gallons of gasoline ? 
Options: a ) 190 , b ) 284.6 , c ) 300 , d ) 256 , e ) 312

Ex Output:

d