The post office returns a patient's bill to the clinic with the notation "address unknown." Which of the following steps are appropriate in handling this situation?
a) Resend the bill to the same address requesting return receipt.
b) Verify the mailing address on file in the clinic database.
c) Call the patient's emergency contact number.
d) Document the postmark date.
e) Prepare a new envelope with the corrected address and new postage.
