(a) The registered agent of a foreign corporation authorized to transact business in this state is the corporation's agent for service of any process, notice, or demand required or permitted by law to be served on the foreign corporation.

(b) If a foreign corporation has no registered agent or its registered agent cannot with reasonable diligence be served, the corporation may be served by registered or certified mail or statutory overnight delivery, return receipt requested, addressed to the chief executive officer, chief financial officer, or secretary of the foreign corporation, or a person holding a position comparable to any of the foregoing, at its principal office shown in the later of its application for a certificate of authority or its most recent annual registration. Any party that serves a foreign corporation in accordance with this subsection shall also serve a copy of the process upon the Secretary of State.

(c) Service is perfected under subsection (b) of this Code section at the earliest of:

(1) The date the foreign corporation receives the mail;

(2) The date shown on the return receipt, if signed on behalf of the foreign corporation; or

(3) Five days after its deposit in the United States mail, as evidenced by the postmark, if mailed postpaid and correctly addressed.

(d) This Code section does not prescribe the only means, or necessarily the required means, of serving a foreign corporation.

(e) For service in a proceeding to enforce any obligation of a domestic corporation party to a merger, see subsection (b) of Code Section 14-3-1106.