Skilled nursing facilities provide extended skilled nursing or rehab care under Medicare Part _______.

Skilled nursing facilities provide extended skilled nursing or rehabilitation care primarily under Medicare Part A. Part A covers inpatient hospital stays and the necessary care received in skilled nursing facilities following a qualifying hospital stay. This includes rehabilitation services, as well as skilled nursing care that is deemed medically necessary.

Additionally, Medicare Part B can cover some outpatient services that might be provided by the skilled nursing facilities but generally focuses on preventive care, outpatient hospital services, and other types of care not covered under Part A. Therefore, since skilled nursing facilities operate under both Parts A and B, the answer encompasses the full range of services provided under Medicare for such facilities.

The inclusion of only Part C or Part D in other choices does not accurately reflect the structure of Medicare when it comes to skilled nursing care. Part C refers to Medicare Advantage plans, which often include both Part A and B benefits offered through private insurance companies, but it is not the direct source for coverage in skilled nursing facilities. Part D handles prescription drug coverage and isn't related to skilled nursing services. Hence, the comprehensive answer of A, covering both Parts A and B, encompasses the true nature of Medicare coverage for skilled nursing facilities.