What does MEA assure regarding navigational signals?

The Minimum Enroute Altitude (MEA) is designed to ensure that pilots have safe vertical clearance from obstacles and provide adequate signal coverage for navigation. Specifically, the MEA guarantees acceptable navigational signal coverage within the airspace and assures that the aircraft remains above all obstacles in the area along the route of flight. Additionally, it ensures that the aircraft will maintain a reliable navigation signal from ground installations, which is essential for course navigation.

In this context, the correct choice emphasizes that maintaining the MEA affords safety concerning obstructions while also upholding adequate navigational signal coverage, which is pivotal for instrument navigation. This means that even in mountainous terrain or areas with potential obstacles, the MEA provides assurance that pilots can navigate safely and maintain instrument flight rules, thereby avoiding hazards while ensuring that navigational equipment can function effectively.