Part A is Hospital Insurance and covers cost associated with confinement in a hospital or skilled nursing facility. (see Medicare Part A)

Medicare Advantage Plans are health plan options that are approved by Medicare but run by private companies. They are part of the Medicare Program, and sometimes called "Part C." When you join a Medicare Advantage Plan, you are still in Medicare. (see Medicare Part C) With Medicare Advantage Plans:

Part B is Medical Insurance and covers physicians services, outpatient care, test, and supplies. (see Medicare Part B)