Unless the bylaws provide otherwise, any action taken by the directors of a close corporation without a meeting called properly and with due notice shall nevertheless be deemed valid if:
(a) Before or after such action is taken, a written consent thereto is signed by all the directors; or
(b) All the stockholders have actual or implied knowledge of the action and make no prompt objection in writing; or
(c) The directors are accustomed to take informal action with the express or implied acquiescence of all the stockholders; or
(d) All the directors have express or implied knowledge of the action in question and none of them makes a prompt objection in writing.
An action within the corporate powers taken at a meeting held without proper call or notice is deemed ratified by a director who failed to attend, unless after having knowledge thereof, the director promptly files his written objection with the secretary of the corporation.