Question: In a 5G network, when constructing an SUCI containing a GLI in NAI format, how is the `username` part of the NAI encoded?
Option 1: As a plain text string identical to the IMSI
Option 2: Using Base64 encoding as specified for HTTP authentication
Option 3: Following the null-scheme but with a prefix indicating the UE's location
Option 4: According to the null-scheme, incorporating `type2.rid0.schid0.userid<username>` where `<username>` is encoded as per the SUPI's username part
Explanation: The correct encoding for the `username` part of the NAI in an SUCI containing a GLI follows the null-scheme, involving a structured format (`type2.rid0.schid0.userid<username>`) where `<username>` is specifically encoded to match the username part of the SUPI, ensuring consistency and security in identifier handling within the network.