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: if 36 men can do a piece of work in 25 hours , in how many hours will 12 men do it ? 
Options: a ) 22 , b ) 38 , c ) 60 , d ) 88 , e ) 75
Example Output: e

Example Input: Problem: a train running at the speed of 120 km / hr crosses a pole in 18 seconds . what is the length of the train ? 
Options: a ) 560 , b ) 570 , c ) 580 , d ) 590 , e ) 600
Example Output: e

Example Input: Problem: excluding stoppages , the speed of a bus is 80 km / hr and including stoppages , it is 70 km / hr . for how many minutes does the bus stop per hour ? 
Options: a ) 11 min , b ) 10 min , c ) 8 min , d ) 6 min , e ) 5 min
Example Output:
c