Subject to Section 912 and except as otherwise provided in this article, the client, whether or not a party, has a privilege to refuse to disclose, and to prevent another from disclosing, a confidential communication between client and lawyer if the privilege is claimed by:
(a) The holder of the privilege;
(b) A person who is authorized to claim the privilege by the holder of the privilege; or
(c) The person who was the lawyer at the time of the confidential communication, but such person may not claim the privilege if there is no holder of the privilege in existence or if he is otherwise instructed by a person authorized to permit disclosure.
The relationship of attorney and client shall exist between a law corporation as defined in Article 10 (commencing with Section 6160) of Chapter 4 of Division 3 of the Business and Professions Code and the persons to whom it renders professional services, as well as between such persons and members of the State Bar employed by such corporation to render services to such persons. The word “persons” as used in this subdivision includes partnerships, corporations, limited liability companies, associations and other groups and entities.