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 searchlight on top of the watchtower makes 4 revolutions per minute . what is the probability that a man appearing near the tower will stay in the dark for at least 12 seconds ? 
Options: a ) 1 / 2 , b ) 2 / 3 , c ) 1 / 3 , d ) 1 / 4 , e ) 1 / 5

Ex Output:
e


Ex Input:
Problem: two trains a and b starting from two points and travelling in opposite directions , reach their destinations 9 hours and 4 hours respectively after meeting each other . if the train a travels at 100 kmph , find the rate at which the train b runs . 
Options: a ) 40 , b ) 60 , c ) 150 , d ) 80 , e ) 100

Ex Output:
c


Ex Input:
Problem: in how many seconds will a train 150 meters long pass an oak tree , if the speed of the train is 36 km / hr ? 
Options: a ) 11 , b ) 13 , c ) 15 , d ) 17 , e ) 19

Ex Output:

c