A person is not eligible for a county office who at the time of election is not:
(1) of the voting age required by the Montana constitution;
(2) a citizen of the state; and
(3) (a) an elector of the county in which the duties of the office are to be exercised; or
(b) in the case of an office consolidated between two or more counties, an elector in one of the counties in which the duties of the office are to be exercised.