Question: What is the primary purpose of the Zn reference point in the Generic Authentication Architecture (GAA) as utilized by the Network Application Function (NAF)?
Option 1: To establish a new HTTP Digest AKA protocol run between the User Equipment (UE) and the Bootstrapping Server Function (BSF).
Option 2: To manage Quality of Service (QoS) parameters for applications utilizing GAA.
Option 3: To retrieve previously agreed key material from the BSF, and optionally, to fetch application-specific user security settings.
Option 4: To handle authentication requests directly between the UE and the NAF.
Explanation: The Zn reference point is specifically defined for the NAF to retrieve key material previously established through an HTTP Digest AKA protocol run from the BSF, and optionally, to fetch application-specific user security settings, aligning with efficient reuse of established secure contexts and tailored security for different applications.