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 rower can row 5 km / h in still water . when the river is running at 2 km / h , it takes the rower 1 hour to row to big rock and back . how many kilometers is it to big rock ? 
Options: a ) 1.5 , b ) 1.8 , c ) 2.1 , d ) 2.4 , e ) 2.7

Ex Output:
c


Ex Input:
Problem: a man can row 8 kmph in still water . when the river is running at 1.2 kmph , it takes him 1 hour to row to a place and black . how far is the place ? 
Options: a ) 3.58 , b ) 3.68 , c ) 3.78 , d ) 3.88 , e ) 3.98

Ex Output:
b


Ex Input:
Problem: a 300 m long train crosses a platform in 39 sec while it crosses a signal pole in 36 sec . what is the length of the platform ? 
Options: a ) 389 m , b ) 350 m , c ) 289 m , d ) 299 m , e ) 25 m

Ex Output:

e