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'.

Example Input: Problem: a train 180 m long is running with a speed of 55 km / hr . in what time will it pass a man who is running at 7 km / hr in the direction opposite to that in which the train is going ? 
Options: a ) 5.5 , b ) 10.45 , c ) 7 , d ) 8 , e ) 9.5
Example Output: b

Example Input: Problem: the length of the bridge , which a train 130 meters long and travelling at 45 km / hr can cross in 30 seconds , is ? 
Options: a ) 288 , b ) 266 , c ) 245 , d ) 277 , e ) 211
Example Output: c

Example Input: Problem: there is a point p on the circle . a and b started running in two constant different speeds . a in clockwise and b in anti - clockwise . first time 500 m in clockwise from p then 400 anti - clockwise . if b is yet to complete one round , what is the circumference of the circle ? 
Options: a ) 700 , b ) 800 , c ) 900 , d ) 1000 , e ) 1100
Example Output:
a