Which of the following features is used when assigning minimum altitudes over certain points by ATC?

The correct answer is identified as MOCA, which stands for Minimum Obstruction Clearance Altitude. MOCA is a significant altitude used by Air Traffic Control (ATC) to ensure aircraft fly clear of obstacles, specifically ensuring a safe vertical distance above terrain and man-made structures. It provides at least 1,000 feet of clearance in non-mountainous areas and 2,000 feet in mountainous regions, adding an essential safety buffer.

In the context of ATC assigning minimum altitudes, MOCA is specifically designed to protect the aircraft during enroute flights by informing pilots of the lowest permissible altitude that maintains safety over obstacles along the route. MOCA is also relevant for pilots because it can ensure navigational signal reception from ground stations within a certain radius.

While other choices represent different altitude designations or regulations, such as MORCA (Minimum Off Route Clearance Altitude), MPA (Minimum Safe Altitude for certain operations), and MVA (Minimum Vectoring Altitude), they do not specifically serve the purpose of defining altitudes for minimum obstruction clearance in the same manner that MOCA does. Therefore, it is MOCA that provides the essential altitude information relevant for safe navigation over specific points as designated by ATC.