(a) The term of office of board members shall be three years, and one third, as nearly as may be possible, shall be elected or appointed every year; provided, that at the inception of any agreement or order the entire board shall be elected or appointed, one third for a term of one year, one third for a term of two years, and one third for a term of three years.
(b) Any marketing agreement or order may provide either for election of board members as specified by such agreement or order or for appointment of board members by the Commission.
(c) Any marketing agreement or order may provide for election or appointment of board members by districts.