Question: What is a requirement for adding vendor-specific attributes to existing 3GPP S NRM Managed Object Classes (MOCs)?
Option 1: The vendor-specific attributes can be directly added to the existing MOCs without any modifications.
Option 2: The existing MOCs must be subclassed, and then vendor-specific attributes can be added while maintaining the superior class's behavior.
Option 3: Vendor-specific attributes can only be added after converting the MOCs into CORBA objects using IDL representation.
Option 4: Adding vendor-specific attributes to existing NRM MOCs is not permitted under any circumstances.
Explanation: This option correctly reflects the requirement that to add vendor-specific attributes to 3GPP S NRM MOCs, subclassing of these MOCs is necessary. This ensures that the specified behavior of the superior (original) classes is maintained while allowing for the addition of new, vendor-specific behavior and attributes. Subclassing prevents direct alteration of standardized MOCs, preserving their integrity.