Question: In an inter-system handover to NG-RAN, who determines the availability of a direct forwarding path between the source Serving and Packet Data Network Gateway (SN) and the target Next Generation Radio Access Network (NG-RAN) node?
Option 1: Source eNB (evolved Node B)
Option 2: Target NG-RAN node with assistance from the Mobility Management Entity (MME)
Option 3: Serving and Packet Data Network Gateway (SN) autonomously
Option 4: Target NG-RAN node
Explanation: In the context of inter-system handover to Next Generation Radio Access Network (NG-RAN), the determination of a direct forwarding path's availability between the source Serving and Packet Data Network Gateway (SN) and the target NG-RAN node is specifically assigned to the target NG-RAN node. This is crucial for efficient handover management, as the target node has the most up-to-date information regarding its connectivity and capabilities.