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: a copy machine , working at a constant rate , makes 40 copies per minute . a second copy machine , working at a constant rate , makes 55 copies per minute . working together at their respective rates , how many copies do the two machines make in half an hour ? 
Options: a ) 90 , b ) 2,700 , c ) 4,500 , d ) 5,400 , e ) 2,850

Ex Output:
e


Ex Input:
Problem: a flagpole 18 meters high casts a shadow of length 45 meters . if a building under similar conditions casts a shadow of length 55 meters , what is the height of the building ( in meters ) ? 
Options: a ) 20 , b ) 22 , c ) 24 , d ) 26 , e ) 28

Ex Output:
b


Ex Input:
Problem: a thief is spotted by a policeman from a distance of 160 meters . when the policeman starts the chase , the thief also starts running . if the speed of the thief be 8 km / hr and that of the policeman 10 km / hr , how far the thief will have run before he is overtaken ? 
Options: a ) 350 m , b ) 240 m , c ) 440 m , d ) 640 m , e ) none of them

Ex Output:

d