What is the vertical limit for Class D airspace?

Class D airspace typically extends from the surface up to a specified ceiling, which is generally established at 2,500 feet above the airport elevation. This classification is designed to provide controlled airspace around airports that have an operating control tower, offering a balance between the need for air traffic control services and the management of air traffic in the vicinity of the airport.

In contrast, other options suggest higher limits or different types of airspace. For example, the mention of 4,000 feet pertains more to Class E airspace under certain conditions, while Class D is specifically limited to the lower range up to 2,500 feet above ground level. Option C implies a more general statement regarding airspace classifications, and option D refers to uncontrolled airspace, which does not accurately define Class D airspace. Thus, the appropriate reference is that Class D airspace is limited vertically to 2,500 feet.