An auditor is performing an audit of the hospital$$s freestanding Emergency Rooms $($FSER$).$ Which of the following would be most concerning to the auditor?

a$.$ Different prices are charged for Level IV ER visits between the FSER and the hospital.

b$.$ The FSER is not within $10$ miles from the hospital.

c$.$ A Medicare patient transferred from the FSER to the hospital was billed for the FSER copayment and inpatient deductible.

d$.$ A commercial patient gets two separate bills for the physician and FSER charges.