Great idea for a quiz, but you REALLY need to fix it. Austrohungary and various derivations of it should be accepted and expecting people to type "Sweden AND Norway" as one answer is frankly daft.
Judging by other comments you may also want to check, San Marino, Monaco, and Bulgaria. As well as your source for Liechenstein's date of independence.
Judging by other comments you may also want to check, San Marino, Monaco, and Bulgaria. As well as your source for Liechenstein's date of independence.