Which class of airspace is characterized by no ATC services being provided?

The correct answer is Class G airspace, which is defined as uncontrolled airspace. This category is characterized by the absence of Air Traffic Control (ATC) services, meaning pilots operating in this airspace do not receive any traffic advisories, instruction, or information from ATC. Consequently, it is the pilot’s responsibility to maintain situational awareness and to follow visual flight rules (VFR) or existing regulations for safe operation.

In Class G airspace, pilots must maintain their own vigilance regarding other aircraft and weather conditions since there is no ATC guidance. This type of airspace typically exists at lower altitudes and is often used for general aviation, where the volume of air traffic is relatively low.

Other classes of airspace, such as Class D and Class E, are controlled airspaces where ATC services are provided. Class F, while sometimes included in discussions, typically refers to specific flight information regions or advisory airspace that may not operate under the same rules. Therefore, it's clear that Class G explicitly denotes airspace where ATC services are not available.