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'.

Ex Input:
Problem: a water tank is four - fifths full . pipe a can fill a tank in 10 minutes and pipe b can empty it in 6 minutes . if both the pipes are open , how many minutes will it take to empty or fill the tank completely ? 
Options: a ) 6 , b ) 9 , c ) 10 , d ) 12 , e ) 15

Ex Output:
d


Ex Input:
Problem: find avrg speed if a man travels at speed of 32 km / hr up and 48 km / hr dawn at an altitude of 230 m . 
Options: a ) 25.8 , b ) 26.8 , c ) 38.4 , d ) 34.4 , e ) 29.8

Ex Output:
c


Ex Input:
Problem: two pipes a and b can fill a tank in 4 and 5 hours respectively . if they are turned up alternately for one hour each , the time taken to fill the tank is ? 
Options: a ) 4 hrs 29 min , b ) 4 hrs 24 min , c ) 8 hrs 24 min , d ) 4 hrs 44 min , e ) 5 hrs 24 min

Ex Output:

b