Question: What happens to the SN RRC and UP keys when the SN releases the last UE radio bearer or when the SN is changed?
Option 1: The SN RRC and UP keys are updated with new values.
Option 2: The SN RRC and UP keys are stored for future use.
Option 3: The SN RRC and UP keys are transferred to a different network node.
Option 4: The SN and UE delete the SN RRC and UP keys.
Explanation: When the SN releases the last UE radio bearer or when the SN is changed, the SN and UE are required to delete the SN RRC and UP keys to ensure security and prevent any potential misuse of these keys. This is a critical step in maintaining the security of the 5G system.