Question: In a UAS (Uncrewed Aerial System) setup, when an immediate change of Command and Control (C2) communication mode is required, what entity can switch the C2 communication link without needing to involve another server?
Option 1: UAE Server
Option 2: Network Operator's Core Network
Option 3: UAE Client (UAV or UAV-C)
Option 4: External Mission Control Station
Explanation: This is correct because, according to the requirements for UAS application layer support, the UAE Client (which can be either the UAV itself or its control station, UAV-C) must have the capability to switch the C2 communication link on its own when an immediate change in the C2 communication mode is necessary. This autonomy ensures prompt adaptation to changing operational needs without delay, enhancing the system's responsiveness and reliability.