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: 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

Ex Output:
d

Ex Input:
Problem: if s = x ^ 4 + y ^ 4 = 100 , then the greatest possible value of x is between
Options: a ) 0 and 3 , b ) 3 and 6 , c ) 6 and 9 , d ) 9 and 12 , e ) 12 and 15

Ex Output:
b

Ex Input:
Problem: a taxi company costs $ 2.75 for the first quarter - mile and 12.5 cents for each additional quarter mile . what is the maximum distance you can travel with $ 6.50 ?
Options: a ) 4 miles , b ) 5 3 / 4 miles , c ) 6 1 / 2 miles , d ) 7 3 / 4 miles , e ) 8 1 / 4 miles

Ex Output:
d