What is Medicare/Medicare Advantage, and who is eligible

•  Medicare is a national Health insurance program in the United States, that started in 1965 under the Social Security Administration(SSA) and now administered by the Centers for Medicare and Medicaid Services (CMS). It primarily provides health insurance for Americans aged 65 and older, but also for some younger people with disability status as determined by the SSA, including people with end stage renal disease and amyotrophic lateral sclerosis(ALS or Lou Gehrig's disease) 

• Part A Medicare covers hospital (inpatient, formally admitted only), skilled nursing (only after being formally admitted to a hospital for three days and not for custodial care), and hospice services.

• Part B Medicare covers outpatient services including some providers' services while inpatient at a hospital, outpatient hospital charges, most provider office visits even if the office is "in a hospital", and most professionally administered prescription drugs..

 Part C is an alternative called Managed Medicare or Medicare Advantage which allows patients to choose health plans with at least the same service coverage as Parts A and B (and most often more), often the benefits of Part D, and always an annual out-of-pocket expense limit which A and B lack. A beneficiary must enroll in Parts A and B first before signing up for Part C