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 prison of 10,000 inmates has enough food to feed them all for 50 days . after 10 days some of the inmates leave and the food is now enough for the same period of 50 days as before . how many of them left ? 
Options: a ) 3,000 , b ) 2,200 , c ) 2,000 , d ) 1,000 , e ) 200

Ex Output:
c


Ex Input:
Problem: a train running at the speed of 60 km / hr crosses a pole in 30 sec . what is the length of the train ? 
Options: a ) 535 m , b ) 178 m , c ) 186 m , d ) 168 m , e ) 500 m

Ex Output:

e