Final answer:
The Billing Department enters revenue codes onto UB-04 forms.
Step-by-step explanation:
The correct answer is a) Billing Department. The Billing Department is responsible for entering revenue codes onto UB-04 forms. UB-04 forms, also known as Uniform Billing Claim forms, are used by healthcare providers to submit claims for reimbursement from insurance companies or government programs. These forms contain information about the services provided by the healthcare provider, including revenue codes that indicate the specific type of service rendered.