Medicare in 90 Seconds: Parts A, B, C, and D

“What are Medicare Parts A, B, C, and D—and which parts do I need for ICHRA (CHOICE)?

Parts A and B are the federal Medicare foundation. Parts C and D are private-plan choices that build on that foundation.

Quick answer

For the benefitbay Medicare + ICHRA (CHOICE) path, you need Medicare Part A and Part B. Together, they are Original Medicare and unlock your next coverage choice. Part C is Medicare Advantage, a private-plan way to receive your A and B benefits. Part D is prescription drug coverage. You will use ICHRA (CHOICE) after your Medicare foundation is active and your eligible premiums are set up.

Part A: Hospital Insurance

Part A helps cover inpatient hospital stays, skilled nursing facility care after a qualifying hospital stay, hospice care, and certain home health services. Many people qualify for premium-free Part A through their own or a spouse’s Medicare-taxed work history. If you do not qualify for premium-free Part A, you can still enroll, but the premium question needs to be part of your Medicare budget conversation.

Part A is not the whole Medicare answer. It is hospital coverage. It does not replace Part B, and Part A alone does not satisfy the Medicare + ICHRA (CHOICE) requirement.

Part B: Medical Insurance

Part B helps cover doctors’ services, outpatient care, preventive services, lab work, imaging, durable medical equipment, outpatient mental health care, and many other medical services. Part B has a monthly premium and cost sharing. It is the part people most often delay without fully understanding the timing consequences.

For ICHRA (CHOICE), Part B is not optional. The Medicare-eligible employee needs both Part A and Part B active before benefitbay can complete the Medicare coverage and premium-payment steps.

Part C: Medicare Advantage

Part C, also called Medicare Advantage, is a Medicare-approved private plan that delivers your Part A and Part B benefits. Many Medicare Advantage plans include Part D drug coverage and may include additional benefits such as dental, vision, or hearing services. You stay enrolled in Medicare and keep paying your Part B premium when you choose Medicare Advantage.

This is one of the two ways to complete your coverage after Parts A and B are active.

Part D: Prescription Drug Coverage

Part D helps pay for outpatient prescription drugs. With Original Medicare, you generally choose a standalone Part D plan. Many Medicare Advantage plans include Part D as part of the plan. Part D is optional, but it is time-sensitive. A long gap without Medicare drug coverage or other creditable drug coverage can create a late-enrollment penalty.

The simple map