Question: Which of the following is NOT a primary category under which the S1 interface functions can be broadly classified?
Option 1: Mobility Management
Option 2: Session Management
Option 3: Network Resource Optimization
Option 4: Signaling Transport and Interface Management
Explanation: The S1 interface functions are primarily categorized into Mobility Management, Session Management, and Signaling Transport and Interface Management. Network Resource Optimization is not a direct primary category, although some functions may indirectly contribute to it.