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: a leak in the bottom of a tank can empty the full tank in 6 hours . an inlet pipe fills water at the rate of 4.5 liters per minute . when the tank is full in inlet is opened and due to the leak the tank is empties in 8 hours . the capacity of the tank is ? 
Options: a ) 5729 , b ) 5760 , c ) 2889 , d ) 6480 , e ) 2799
Example Output: d

Example Input: Problem: two passenger trains start at the same hour in the day from two different stations and move towards each other at the rate of 16 kmph and 21 kmph respectively . when they meet , it is found that one train has traveled 60 km more than the other one . the distance between the two stations is ? 
Options: a ) 2887 , b ) 444 , c ) 877 , d ) 278 , e ) 178
Example Output: b

Example Input: Problem: a and b can do a work in 10 days and 15 days respectively . a starts the work and b joins him after 3 days . in how many days can they complete the remaining work ? 
Options: a ) 6 days , b ) 2 days , c ) 8 days , d ) 4 1 / 5 days , e ) 9 days
Example Output:
d