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: the speed at which a man can row a boat in still water is 16 kmph . if he rows downstream , where the speed of current is 4 kmph , what time will he take to cover 100 metres ?
Options: a ) 23 , b ) 27 , c ) 28 , d ) 12 , e ) 18
Example Output: e

Example Input: Problem: a train running at the speed of 60 km / hr crosses a pole in 6 sec . what is the length of the train ?
Options: a ) 356 , b ) 278 , c ) 127 , d ) 100 , e ) 150
Example Output: d

Example Input: Problem: how many seconds will a train 150 meters long take to cross a bridge 150 meters long if the speed of the train is 36 kmph ?
Options: a ) 28 sec , b ) 23 sec , c ) 29 sec , d ) 30 sec , e ) 36 sec
Example Output:
d