What does the "C" in Class C airspace signify?

Class C airspace is designed to provide a safe and organized environment for airports with a significant amount of air traffic. The "C" stands for "cities of sizable operations," which relates to the airspace surrounding major airports that handle a considerable volume of commercial and general aviation traffic. This airspace typically includes at least a basic radar service and requires aircraft operating within it to establish two-way radio communication with Air Traffic Control (ATC).

As a result, the nature of Class C airspace is fundamentally linked to cities and their major airports that support significant operational activity, ensuring a structured approach to air traffic management in busy areas. The other options do not accurately capture the primary purpose of Class C airspace or its relation to air traffic control and airport operations.