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 train 284 m in length crosses a telegraph post in 18 seconds . the speed of the train is ? 
Options: a ) 77 kmph , b ) 55 kmph , c ) 57 kmph , d ) 58 kmph , e ) 76 kmph

Ex Output:
c


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: imagine an analog clock set to 12 o ' clock . note that the hour and minute hands overlap . how many times each day do both the hour and minute hands overlap ? how would you determine the exact times of the day that this occurs ? 
Options: a ) 11 , b ) 12 , c ) 22 , d ) 24 , e ) 44

Ex Output:

c