A Medicare Advantage plan otherwise known as Medicare Part C is an alternative to Original Medicare giving you your part A and B benefits under one umbrella. Essentially your medicare benefits helps pay the premium for a private insurance company instead of providing coverage directly for your medical needs. Medicare Part C combines Part A and Part B and often Part D prescription drugs. Medicare Part C usually offers extra benefits for services such as dental, vision and low to no copays on physician visits. You must have Medicare Part A and B to enroll in a Medicare Advantage plan.