As used in this article, “holder of the privilege” means:
(a) The client, if the client has no guardian or conservator.
(b) A guardian or conservator of the client, if the client has a guardian or conservator.
(c) The personal representative of the client if the client is dead, including a personal representative appointed pursuant to Section 12252 of the Probate Code.
(d) A successor, assign, trustee in dissolution, or any similar representative of a firm, association, organization, partnership, business trust, corporation, or public entity that is no longer in existence.