>the familiy name or
>the own name before wedding or
>a combination of both familiy name-own name or vice versa. Except the name of both before wedding was identicaly.

I know of a case when both of them had the same last name before marying, and that the clerk had to go through motions asking them which combination they wanted: to keep their old surnames (Petrović and Petrović), to take the surname of the other (Petrović) or to append (become Petrović-Petrović).