Question: Under what condition will an S-CSCF store user information during the deregistration of a Public User Identity?
Option 1: When it sends a Server-Assignment-Request with Server-Assignment-Type set to USER_DEREGISTRATION_STORE_SERVER_NAME or TIMEOUT_DEREGISTRATION_STORE_SERVER_NAME and receives a DIAMETER_SUCCESS response from the HSS.
Option 2: Automatically, for all deregistrations, to maintain a user history.
Option 3: Only if the deregistration is initiated by the User Equipment (UE).
Option 4: Never, as user information is always discarded upon deregistration.
Explanation: This option is correct because it aligns with the specified condition under which an S-CSCF will store user information during deregistration. The condition requires two key elements: (1) sending a Server-Assignment-Request with a specific Server-Assignment-Type, and (2) receiving a DIAMETER_SUCCESS response from the HSS, ensuring user data is retained only when explicitly requested and successfully acknowledged.