Why Correct: None of these three European microstates has a full-service airport. Monaco has a heliport but no runway for fixed-wing aircraft. San Marino has no airport; the nearest major airport is Federico Fellini International in Rimini, Italy. Andorra also has no airport; the closest airports are in Barcelona, Spain and Toulouse, France.
Distractor Analysis: Monaco has only a heliport, not a conventional airport. San Marino lacks any airport. Andorra lacks any airport. Therefore all three qualify as having no airport, making 'All of the above' the correct comprehensive choice.
Takeaway: Remember these three European microstates with no airports: Monaco (heliport only), San Marino, and Andorra. The Vatican City also has no airport; it uses Rome's airports. Useful for static GK and world geography questions.