You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For consistency, answers should be in all lower cased letters.

[Q]: Category: LARGE EQUIPMENT 
Clue: For smooth travel, ballast tampers & ballast regulators keep the gravel at the right level among these
[A]: railroad tracks


[Q]: Category: DR. SEUSS CHARACTERS 
Clue: This turtle was king of the pond at the island of Sala-ma-Sond
[A]: yertle the turtle


[Q]: Category: EUROPE 
Clue: This principality nestled between Austria & Switzerland has no army; it was abolished in 1868
[A]:
liechtenstein