Question: When a UE transitions to EMM-DEREGISTERED due to a UE-initiated detach with a reason other than 'switch off', what happens to the remaining authentication data in the UE and MME?
Option 1: All remaining authentication data is removed from both the UE and MME.
Option 2: The current native EPS NAS security context is deleted, but unused authentication vectors are kept.
Option 3: Only the current native EPS NAS security context is kept, and all other authentication data is removed.
Option 4: All remaining authentication data is kept in both the UE and MME.
Explanation: According to the specified behavior for a UE-initiated detach where the reason is not 'switch off', both the MME and UE are instructed to keep all the remaining authentication data, ensuring continuity for potential future connections without requiring full re-authentication. This highlights the importance of managing security contexts during state transitions in telecom networks to balance security with operational efficiency.