What are the dimensions of Class D airspace?

Class D airspace is typically defined as a cylindrical area that surrounds an airport with an operational control tower. The standard dimensions of Class D airspace are a radius of 4 nautical miles from the airport's center and extending vertically from the surface up to 2,500 feet above the airport elevation. This configuration provides controlled airspace around airports to manage air traffic effectively and ensure safety for both arriving and departing flights, as well as for other aircraft operating within the vicinity.

This makes the answer valid, as it aligns perfectly with the specified dimensions for Class D airspace. The varying dimensions in the other options do not correspond to the established criteria for Class D airspace, making them incorrect.