To me, "temporary" would seem to imply that you have a definite timescale for returning to the U.S. (e.g., you're posted abroad with the military or are studying at a foreign university). So I would probably put "indefinite," but it might be worth ringing/e-mailing the county clerk's office (or whoever handles registration in your home state) to find out for sure.
Are you filling out an application for Texas, BTW? I just filled out my application for West Virginia, and it doesn't ask that question.