Final answer:
Medicare Part D is prescription drug coverage designed to help Medicare beneficiaries with the costs of their medications. It fills a gap in the original Medicare coverage and is funded through beneficiary premiums and general revenues.
Step-by-step explanation:
Medicare Part D is prescription drug coverage. It is neither hospital insurance, medical insurance, nor a Medicare Advantage Plan. Introduced through the Medicare Prescription Drug and Modernization Act of 2003, Part D was specifically designed to help cover the cost of prescription drugs for Medicare beneficiaries. It addresses a critical need, as prior to Part D, Medicare had substantial gaps in coverage, particularly for prescription medications, which are often a necessity for both the elderly and disabled. Funding for Medicare Part D comes from the Supplementary Medical Insurance trust fund and is financed through beneficiary premiums (about 25%) and general revenues (about 75%).