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: if a train , travelling at a speed of 360 kmph , crosses a pole in 5 sec , then the length of train is ? 
Options: a ) 381 m , b ) 112 m , c ) 500 m , d ) 125 m , e ) 433 m

Ex Output:
c


Ex Input:
Problem: town m town n town o town p town q town r ; town a town b town c town d town e town f in the table above , what is the least number of table entries that are needed to show the mileage between each town and each of the other 5 towns ? 
Options: a ) 11 , b ) 12 , c ) 13 , d ) 14 , e ) 15

Ex Output:
e


Ex Input:
Problem: it takes avery 4 hours to build a brick wall while tom can do it in 2 hours . if the two start working together and after an hour avery leaves , how much time will it take tom to complete the wall on his own ? 
Options: a ) 20 , b ) 40 , c ) 30 , d ) 50 , e ) 60

Ex Output:

c