(a) Each corporation must have a board of directors.

(b) Except as provided in this chapter or subsection (c) of this Code section, all corporate powers shall be exercised by or under the authority of, and the business and affairs of the corporation managed under the direction of, its board.

(c) No limitation upon the authority of the directors, whether contained in the articles of incorporation or bylaws, shall be effective against persons, other than members and directors, who are without actual knowledge of the limitation.

(d) The articles may authorize a person or persons to exercise some or all of the powers which would otherwise be exercised by a board. To the extent so authorized any such person or persons shall have the duties and responsibilities of the directors, and the directors shall be relieved to that extent from such duties and responsibilities.