(a) The patient is the holder of the privilege.
(b) The following persons may claim the privilege on the patient's behalf:
(1) a person authorized to act on the patient's behalf;
(2) a dentist acting on the patient's behalf; and
(3) an agent or employee of a person listed in Subdivision (1) or (2).
(c) A person's authority to claim the privilege is presumed in the absence of evidence to the contrary.