because terms "Prijestolnica" or "Glavni grad" (in English "Capital city") are used in the Croatian language
for the Capitals of Countries. Croatians regions are in Croatian called "Županija" (in English "County").
So, the better title for the quiz would be "Sjedišta Hrvatskih Županija".
Here is list of counties for help: https://en.wikipedia.org/wiki/Counties_of_Croatia