(a) In this section, "vacancy" means a vacancy in the office of director that occurs for any reason, including an office that is vacant because:
(1) a director was disqualified under Section 775.0355; or
(2) no candidate filed for election to the office.
(b) This section applies only to a district located wholly in a county:
(1) with a population of more than three million;
(2) with a population of more than 200,000 that borders Lake Palestine; or
(3) with a population of less than 200,000 that borders another state and the Gulf Intracoastal Waterway.
(c) Not later than the 90th day after a board vacancy occurs, the remaining board members shall appoint a person to fill the unexpired term.
(d) A person appointed under this section must be eligible to serve under Section 775.0345.