Which of the following is NOT a primary responsibility of Air Traffic Control?

Providing in-flight entertainment is not a responsibility of Air Traffic Control. The role of Air Traffic Control primarily revolves around ensuring the safe and orderly flow of air traffic in the skies and on the ground. This includes monitoring aircraft movements to track their locations and ensure they are separated safely from one another, coordinating takeoffs and landings to manage the flow of traffic at airports, and ensuring airspace safety by providing guidance to pilots and managing airspace. In-flight entertainment, however, is a service typically offered by airlines to enhance passenger experience during flights and is not within the scope of responsibilities for Air Traffic Control.