Question: What type of protection should the 3GPP system provide for identities related to the Unmanned Aerial System (UAS) and personally identifiable information?
Option 1: Integrity protection
Option 2: Availability protection
Option 3: Authentication protection
Option 4: Confidentiality protection
Explanation: The 3GPP system should protect the identities related to the UAS and personally identifiable information from unauthorized access, which is achieved through confidentiality protection. This ensures that sensitive information remains private and secure.