After paying an insurance copay at the time of service, a patient receives a subsequent statement for a balance due from their provider. This would be correct under the following scenario: 

A. The patient had not met their deductible and was balance billed. 

B. It is inappropriate for the patient to be balanced billed under any circumstance 

C. The provider performed non-covered services, unaware they were not covered, and did not notify the patient. 

D. The provider is a participating with the insurance company and billed the patient for the difference between the insurance company's allowable amount and payment.