If a subscription contract of a hospital and medical service corporation provides for or offers reimbursement for any service which is within the lawful scope of the practice of a psychologist holding a certificate or license issued by the state in which the services are rendered, a subscriber covered under such contract may select either a physician or duly certified or licensed psychologist to provide the examination, care or treatment for which the subscriber is eligible and which falls within the scope of practice of the psychologist or physician.