What is the typical altitude limit of controlled airspace?

The typical altitude limit of controlled airspace varies depending on the specific type of controlled airspace being considered. Generally, controlled airspace starts from the surface and can extend up to 10,000 feet in a variety of specific classifications, but certain types of controlled airspace can allow for altitudes above 10,000 feet, particularly in Class A airspace, which starts at 18,000 feet.

The correct answer recognizes that while many controlled airspace categories do operate below 10,000 feet, controlled airspace itself can extend significantly higher, especially when considering the broader context of aviation regulations and the various classifications of airspace.

The other options do not accurately represent the usual operational altitudes associated with controlled airspace. For example, limits of 4,000 feet or 8,000 feet do not encompass the full range seen in various controlled airspace definitions. Similarly, the range of 2,500 to 10,000 feet excludes the possibility of airspace that serves flights operating at higher altitudes. Thus, choosing an option that reflects airspace above 10,000 feet aligns more closely with the realities of aviation operations within controlled airspace contexts.