CSS Profile - Only one drop down box under 'residence of parents' for married parents living apart?

We still see my dad on holidays, though. They also file their taxes as joint so I’m supposing I have to put them down as married. I’m just confused as to what happens now that there’s only one drop down box; I can’t put me and my mom’s current country as their country of residence when one parent doesn’t live here, right? Is this along with them living apart for a long time grounds enough for filing them as separated? Thanks again for your time!