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 an object travels at eight feet per second , how many feet does it travel in one hour ? 
Options: a ) 34880 , b ) 3778 , c ) 12788 , d ) 18000 , e ) 28800
Example Output: e

Example Input: Problem: a and b together can do a work in 4 days . if a alone can do it in 20 days . in how many days can b alone do it ? 
Options: a ) 11 , b ) 5 , c ) 6 , d ) 8 , e ) 25
Example Output: b

Example Input: Problem: a car gets 20 kilometers per gallon of gasoline . how many gallons of gasoline would the car need to travel 180 kilometers ? 
Options: a ) 8.5 gallons , b ) 9 gallons , c ) 6.5 gallons , d ) 5.5 gallons , e ) 6 gallons
Example Output:
b