Nice quiz, I was not aware that all those italian cities were city-states once. One detail : Genoa is not on the adriatic sea, but on the ligurian sea (you could as well say it is in Liguria...).
This. Genoa was (briefly) a Mediterranean sea power, not in the Adriatic. Also, it's far from confirmed that Columbus was born there. t's true that there was a family with this name in the city, but it was a very popular surname across the Mediterranean at the time.
The problem with these quiz is that often I don't know the english name of the answer, for example Genua instead of Genova, Syracuse instead of Siracusa and so on. The time available ends up before I have tried all possible combination.
It says "is" instead of "in" in your note at the top of the quiz, by the way.