Final answer:
A provider number is indeed assigned by a payer such as Medicare, Medicaid, or private insurers, to uniquely identify health care providers for transactions and claims processing.
Step-by-step explanation:
The statement that a provider number is assigned by a payer is A. True. A provider number, often referred to as a provider identification number (PIN) or national provider identifier (NPI), is a unique identification number assigned to health care providers in the United States by payers, which include Medicare, Medicaid, and private health insurance companies. This number is essential for the processing of medical claims and is used to identify the provider in health care transactions.