Question: What happens during a 5G-SRVCC handover from NG-RAN to UTRAN for an emergency PDU connection that was previously using the "null integrity protection algorithm" 5G-IA0 in N1 mode?
Option 1: The MS and network perform key derivation using the existing security context.
Option 2: The MS and network do not perform key derivation.
Option 3: The MS and network renegotiate the security parameters to ensure compatibility with UTRAN.
Option 4: The emergency PDU connection is released due to incompatible security settings.
Explanation: According to the specifications, when an emergency PDU connection using the "null integrity protection algorithm" 5G-IA0 in N1 mode undergoes a 5G-SRVCC handover from NG-RAN to UTRAN, neither the MS (Mobile Station) nor the network performs key derivation. This is because the null integrity protection algorithm does not provide any cryptographic material that could be used for key derivation.