What is Medicare?
Medicare is a federal health insurance program for people who are 65 and older, certain younger people with disabilities, and people with End Stage Renal Disease (permanent kidney failure requiring dialysis or a transplant).
What is Medicare Part A (Hospital Insurance)?
Part A covers inpatient hospital stays, care in skilled nursing facilities, and some home health care.
What is Medicare Part B (Medical Insurance)?
Part B covers services from physicians and other health care providers, outpatient care, home health care, durable medical equipment, x-rays and lab tests.
What is Medicare Part C (Medicare Advantage Plans)? 
Part C includes all benefits and services covered under Part A and Part B and usually includes prescription coverage (Part D). Medicare Advantage Plans are run by Medicare-approved private insurance companies.
What is Medicare Part D (Prescription Drug Plans)?
Part D helps cover the cost of prescription drugs and is run by Medicare-approved private insurance companies.