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: excluding stoppages , the speed of a bus is 58 kmph and including stoppages , it is 40 kmph . for how many minutes does the bus stop per hour ? 
Options: a ) 19 , b ) 19.13 , c ) 10.5 , d ) 11.35 , e ) none of these
Example Output: a

Example Input: Problem: a train 1500 m long can cross an electric pole in 50 sec and then find the speed of the train ? 
Options: a ) 106 , b ) 107 , c ) 108 , d ) 109 , e ) 110
Example Output: c

Example Input: Problem: a certain number of workers can do a work in 25 days . if there were 10 workers more it could be finished in 10 days less . how many workers are there ? 
Options: a ) 15 , b ) 30 , c ) 28 , d ) 24 , e ) 32
Example Output:
a