Question: In the context of 3GPP Generic User Profile (GUP), what additional specification, apart from OASIS SOAP Message Security, MUST be adhered to for constructing, decorating, and using the `<wsse:Security>` header element?
Option 1: IETF Transport Layer Security (TLS) Specification
Option 2: Liberty Alliance Security Mechanisms Specification
Option 3: W3C XML Encryption Specification
Option 4: ITU-T X.509 Specification
Explanation: The correct answer is Option 2 because, in addition to adhering to the OASIS SOAP Message Security specification for the `<wsse:Security>` header element in GUP, it is also mandatory to adhere to the mechanisms defined in the Liberty Alliance Security Mechanisms specification, ensuring comprehensive security protocol adherence in the GUP context.