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: in what time will a railway train 80 m long moving at the rate of 40 kmph pass a telegraph post on its way ? 
Options: a ) 3 , b ) 5 , c ) 4 , d ) 6.4 , e ) 7.2
Example Output: e

Example Input: Problem: an aeroplane covers a certain distance at a speed of 240 kmph in 5 hours . to cover the same distance in 123 hours , it must travel at a speed of : 
Options: a ) 234 , b ) 377 , c ) 720 , d ) 378 , e ) 268
Example Output:
d