Question: In which scenario is a UE in RM-DEREGISTERED state able to request IMS Emergency services with authentication?
Option 1: When the UE has an ongoing PDU Session and initiates a new bearer for emergency services.
Option 2: When the UE is redirected to EUTRAN for IMS Emergency services and receives a protected redirect command from the gNB.
Option 3: When the UE has a valid subscription and is authenticated when it registers with the network.
Option 4: When the UE shares a security context with the AMF and initiates a session management message to setup a new bearer for emergency services.
Explanation: According to the provided text, in scenario a), a UE in RM-DEREGISTERED state can request IMS Emergency services if it has a valid subscription and is authenticated when it registers with the network. This ensures that the UE's identity is verified before providing emergency services.