In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Ex Input:
Problem: buses a and b start from a common bus stop x . bus a begins to travel in a straight line away from bus b at a constant rate of 20 miles per hour . one hour later , bus b begins to travel in a straight line in the exact opposite direction at a constant rate of 80 miles per hour . if both buses travel indefinitely , what is the positive difference , in minutes , between the amount of time it takes bus b to cover the exact distance that bus a has covered and the amount of time it takes bus b to cover twice the distance that bus a has covered ? 
Options: a ) 36 , b ) 72 , c ) 132 , d ) 144 , e ) 180

Ex Output:
c


Ex Input:
Problem: convert 0.35 in to a vulgar fraction ? 
Options: a ) 18 / 50 , b ) 16 / 50 , c ) 7 / 20 , d ) 19 / 50 , e ) none

Ex Output:
c


Ex Input:
Problem: if the perimeter of a rectangular garden is 1800 m , its length when its breadth is 400 m is ? 
Options: a ) 500 , b ) 600 , c ) 700 , d ) 800 , e ) 900

Ex Output:

a