Which fee may be added to the member's monthly plan for late enrollment in Medicare?

The Late Enrollment Penalty (LEP) is the correct answer because it specifically addresses the situation of beneficiaries who do not sign up for Medicare when they are first eligible and delay their enrollment. When individuals miss their initial enrollment period without a qualifying reason, they may face a penalty that increases their monthly premium for Medicare Part B and/or Part D.

The LEP is calculated based on the number of full months that the individual was eligible for Medicare but did not sign up for it. This penalty serves as a financial deterrent to encourage timely enrollment in the program, promoting its sustainability and ensuring that beneficiaries utilize services when they need them.

Other options, such as the Early Enrollment Bonus, Annual Coverage Adjustment, and Member Retention Fee, do not apply to the context of late enrollment in Medicare. They either do not exist or do not have regulations tied to enrollment periods, making them irrelevant in the context of penalties for late enrollment.