How far does the MSA extend horizontally from the airport?

The correct answer is that the MSA extends horizontally from the airport by 25 nautical miles. The Minimum Safe Altitude (MSA) is designed to provide pilots with a safe vertical clearance from obstacles in the vicinity of an airport. The 25 nautical mile radius allows for an adequate buffer zone to account for terrain and other obstacles while ensuring that pilots can maintain a safe altitude during their approach or departure from the airport.

This range has been established as part of aviation safety standards to promote safe operations around airports, especially in areas where terrain may rise sharply or in urban environments where man-made structures could pose a hazard. The other choices present distances that do not align with established aviation guidelines for MSAs, which is why 25 nautical miles is the appropriate and correct distance.