Which of the following is covered by Part B of Medicare?

Part B of Medicare primarily covers a range of outpatient services, including care from healthcare providers, preventive services, and various medically necessary supplies. This coverage extends to services like doctor visits, outpatient hospital care, and certain home health services. The primary focus is on outpatient care rather than inpatient services.

In this context, the other options refer to different types of coverage or services. Inpatient hospital stays are covered under Part A of Medicare, which addresses hospital insurance. Prescription drug coverage typically falls under Part D of Medicare, which is specifically designed for medications. Nursing home care may be partially covered by Part A for a limited time if it follows a qualifying hospital stay but is not primarily covered under Part B. Thus, the only correct choice that aligns with what Part B encompasses is outpatient care and services from healthcare providers.