Question: What ciphering algorithms must a User Equipment (UE) implement for confidentiality protection in a 5G system?
Option 1: NEA0, 128-NEA1, and 128-NEA2
Option 2: 128-NEA3 only
Option 3: NEA0 and 128-NEA1 only
Option 4: No specific ciphering algorithms are mandated
Explanation: According to the security architecture and procedures for 5G systems, a UE must support ciphering of user data between the UE and the gNB using specific algorithms. The mandatory ciphering algorithms for confidentiality protection in this context are NEA0, 128-NEA1, and 128-NEA2 as defined in Annex D of the document.