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 crow leaves its nest , and flies back and forth from its nest to a nearby ditch to gather worms . the distance between the nest and the ditch is 100 meters . in one and a half hours , the crow manages to bring worms to its nest 15 times . what is the speed of the crow in kilometers per hour ? 
Options: a ) 1 , b ) 2 , c ) 3 , d ) 5 , e ) 7

Ex Output:
d


Ex Input:
Problem: if a truck is traveling at a constant rate of 54 kilometers per hour , how many seconds will it take the truck to travel a distance of 600 meters ? ( 1 kilometer = 1000 meters ) 
Options: a ) 18 , b ) 24 , c ) 30 , d ) 36 , e ) 40

Ex Output:
e


Ex Input:
Problem: the time taken by a man to row his boat upstream is twice the time taken by him to row the same distance downstream . if the speed of the boat in still water is 42 kmph , find the speed of the stream ? 
Options: a ) 16 kmph , b ) 18 kmph , c ) 14 kmph , d ) 79 kmph , e ) 27 kmph

Ex Output:

c