Final answer:
The correct statement is D. Medicare is the primary payer.
Step-by-step explanation:
The correct statement is D. Medicare is the primary payer.
When an individual continues working after the age of 65 and is covered through their employer's Group Health Plan, Medicare becomes the secondary payer. The Group Health Plan becomes the primary payer, meaning it pays first for any healthcare expenses. Medicare comes in second to cover any remaining costs that the Group Health Plan doesn't pay for.
For example, if Mark's Group Health Plan covers 80% of his healthcare expenses, Medicare will cover the remaining 20% as the secondary payer.