Correct Answer: F. None of them has an airport!
Liechtenstein - It is only a heliport. The nearest major international airport is Zurich, Switzerland.
Andorra - By population and land area, Andorra is the largest of the five countries but it has only one heliport. The nearest airports are Barcelona, Spain and Toulouse, France.
Vatican City - It would be physically impossible to fit a whole airport into the land area but there is a heliport. The nearest airport is Rome (Fiumicino) Airport.
San Marino - San Marino has a heliport only. The nearest airport is in Rimini, Italy.
Monaco - Monaco also only has a heliport. The nearest airport is Cote D'Azur Airport in Nice, France.