What type of airspace requires clearance to operate and extends from the surface to a specified upper limit?

The type of airspace that requires clearance to operate and extends from the surface to a specified upper limit is control zones. Control zones are designated areas around airports where air traffic control (ATC) is responsible for managing all aircraft movements, ensuring safety and preventing collisions. These zones are established to provide a controlled airspace environment for aircraft, particularly those entering or leaving busy airports.

In control zones, pilots must obtain explicit clearance from ATC before entering or operating within the airspace. This ensures that all aircraft movements are coordinated, as there might be a high volume of traffic and various flight operations taking place. The boundaries of control zones vary depending on the airport and its traffic patterns, but they typically extend from the surface up to a specified altitude.

The other options refer to different classes of airspace. Control areas are larger airspaces that also require ATC services, but they are not specifically bound to the surface. Flight information regions provide information service but do not require ATC clearance for entry. General aviation areas are designed for leisure flying and do not require clearance, making them less structured than control zones.