(a) Except as provided by Subsection (b), to be qualified for election as a supervisor:
(1) a person must be:
(A) a resident of this state;
(B) the owner of taxable property in the district; and
(C) at least 18 years of age; or
(2) a person must be a registered voter of the district.
(b) To be qualified for election as a supervisor of a district located wholly or partly in Denton County, a person must be a registered voter of the district.