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 passes a station platform in 31 sec and a man standing on the platform in 20 sec . if the speed of the train is 54 km / hr . what is the length of the platform ? 
Options: a ) 228 , b ) 240 , c ) 165 , d ) 166 , e ) 1811

Ex Output:
c


Ex Input:
Problem: a can do a piece of work 60 days . b can do work in 20 days . in how many days they will complete the work together ? 
Options: a ) 12 days , b ) 16 days , c ) 15 days , d ) 17 days , e ) 18 days

Ex Output:
c


Ex Input:
Problem: a train travels 125 km in 2.5 hours and 270 km in 3 hours . find the average speed of train . 
Options: a ) 80 kmph , b ) 60 kmph , c ) 72 kmph , d ) 90 kmph , e ) none of these

Ex Output:

c