When should control of an aircraft be assumed?

The correct choice emphasizes that control of an aircraft should be assumed after it is within your area of jurisdiction. This principle ensures that the controller has the authority and responsibility for the safety and management of the airspace surrounding that aircraft. Once an aircraft enters your designated area, it becomes your duty to monitor and direct its movements in accordance with air traffic regulations, ensuring safe separation from other aircraft and responding appropriately to any operational changes or emergencies.

This sequence is crucial as it aligns with standard air traffic control procedures that necessitate clear delineation of airspace authority. By waiting until the aircraft is within your jurisdiction before assuming control, you can effectively coordinate with other controlling entities and ensure that you are acting within the legal boundaries of your responsibilities. Additionally, this helps prevent confusion and potential safety hazards that might arise if attempted coordination were made before the aircraft was physically present in the controlled airspace.