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 tank can supply water to a village for 60 days . if a leak at the bottom of the tank drains out 10 liters per day , the supply lasts for 45 days only . for how many days will the supply last if the leak drains out 20 liters per day ? 
Options: a ) 15 , b ) 18 , c ) 20 , d ) 24 , e ) 36
Example Output: e

Example Input: Problem: a train 140 m long is running with a speed of 50 km / hr . in what time will it pass a man who is running at 4 km / hr in the direction opposite to that in which the train is going ? 
Options: a ) 8.1 , b ) 7.0 , c ) 9.33 , d ) 8 , e ) 9
Example Output: c

Example Input: Problem: the sum of four consecutive numbers is 102 . the greatest among these three number is : 
Options: a ) 26 , b ) 28 , c ) 29 , d ) 30 , e ) 27
Example Output:
e