If an Insurance Company Has Rejected a Claim Because No

If an insurance company has rejected a claim because no preauthorization was obtained, what should your medical office do?

A) Write a letter of appeal and review the patient's contract.
B) Bill the patient.
C) Resubmit the claim with proper preauthorization.
D) Call the carrier, and take the company to court if necessary.
E) Write off the claim as a loss.