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: how many seconds will a train 120 meters long take to cross a bridge 200 meters long if the speed of the train is 36 kmph ? 
Options: a ) 22 sec , b ) 32 sec , c ) 25 sec , d ) 24 sec , e ) 31 sec
Example Output: b

Example Input: Problem: a train passes a station platform in 35 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 ) 225 , d ) 166 , e ) 1811
Example Output: c

Example Input: Problem: to fill a tank , 20 buckets of water is required . how many buckets of water will be required to fill the same tank if the capacity of the bucket is reduced to one - fifth of its present ? 
Options: a ) 100 , b ) 200 , c ) 300 , d ) 400 , e ) 500
Example Output:
a