Question: What triggers the establishment of an "NG-RAN node UE context" in a target NG-RAN node during handover procedures?
Option 1: Completion of Handover Resource Allocation during Handover Preparation
Option 2: Receipt of Initial UE Message over the NG-C Interface
Option 3: Successful Authentication of the UE with the AMF
Option 4: Establishment of a UE-associated Logical Xn-Connection
Explanation: According to the definitions related to UE associations in NG-RAN nodes, an "NG-RAN node UE context" is established in the target NG-RAN node after completion of Handover Resource Allocation during Handover Preparation. This ensures that necessary information (e.g., UE state, security, capabilities, and identities of UE-associated logical connections) is available for maintaining NG-RAN services towards the active UE post-handover.