Question: Which reference point does IM-UU utilize for supporting identity management function interactions between the client and server in a 5G System (5GS) or Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access?
Option 1: N1 Reference Point for UE - AMF (Access and Mobility Management Function) interaction
Option 2: F1 Reference Point for CU (Central Unit) - DU (Distributed Unit) interaction in a 5G RAN
Option 3: Xn Reference Point for inter-gNB (next-generation Node Base) interaction in 5GS
Option 4: Uu Reference Point for UE - gNB (next-generation Node Base)/eNodeB interaction
Explanation: The correct answer is Option 4 because IM-UU utilizes the Uu reference point, facilitating direct communication between User Equipment (UE) and base stations (gNB in 5G or eNodeB in LTE/E-UTRAN), ensuring efficient and secure identity management communication between the UE's client and the network's server at the radio access layer.