A person who misses the Initial Enrollment Period for Medicare Part B and has no employer group coverage must wait for the General Enrollment Period, which runs:

Why A is correct

The General Enrollment Period (GEP) for Medicare Part B runs January 1 through March 31 each year. It is the annual catch-up window for people who missed their Initial Enrollment Period and do not qualify for a Special Enrollment Period (for example, because they had no employer group coverage). Coverage purchased during the GEP begins July 1 of the same year, and a late-enrollment penalty generally applies for every 12 months of delay. The GEP runs on a fixed annual calendar.

Why the other options are wrong

• B) October 15 through December 7 is the Annual Election Period for Medicare Advantage and Part D plan changes, not the Part B GEP. The AEP is a separate window for plan changes.
• C) July 1 through September 30 is not an enrollment window for Medicare Part B. That mid-year window is not a Part B enrollment period under the Medicare enrollment rules at all.
• D) April 1 through June 30 is not an enrollment window for Medicare Part B. That spring window is not a Part B enrollment period either, under any Medicare rule at all.

Memory hook

GEP = the January-to-March second chance for Part B, with coverage starting July 1 and a late penalty riding along.