Final answer:
The fact about Medicare Prescription Drug Plans is that to enroll, the consumer must reside in the plan's service area. The benefits of these plans vary and not all drugs are covered.
Step-by-step explanation:
When considering Medicare Prescription Drug Plans, it's important to discern the facts. The correct statement regarding these plans is: To enroll, the consumer must reside in the plan's service area. Medicare Part D is not part of Medicare Supplement Insurance Plans; rather, it is a separate prescription drug plan. Additionally, it is not true that all drugs are covered under Medicare Part D, as the specific coverage can vary based on the chosen plan. Finally, the benefits certainly do vary by plan, as each prescription drug plan might offer different coverage options and costs.