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 man can row upstream at 15 kmph and downstream at 25 kmph , and then find the speed of the man in still water ? 
Options: a ) 27 , b ) 29 , c ) 30 , d ) 20 , e ) 24

Ex Output:
d


Ex Input:
Problem: calculate the circumference of a circular field whose radius is 8 centimeters . 
Options: a ) 17 π cm , b ) 18 π cm , c ) 1 π cm , d ) 16 π cm , e ) 6 π cm

Ex Output:
d


Ex Input:
Problem: a train 125 m long passes a man , running at 10 km / hr in the same direction in which the train is going , in 10 seconds . the speed of the train is ? 
Options: a ) 36 , b ) 50 , c ) 55 , d ) 26 , e ) 29

Ex Output:

c