Question: When a PCRF decides to terminate an IP-CAN session due to reaching a usage quota, which message does it send to the PCEF, and what is included in this message?
Option 1: RAR command with Session-Release-Cause AVP for immediate termination
Option 2: CCA command without any specific AVP related to session termination
Option 3: CCA command including the Session-Release-Cause AVP for context-aware termination
Option 4: RAA command as a response to a PCEF's CCR command, not initiating termination
Explanation: When the PCRF decides to terminate an IP-CAN session (e.g., due to a usage quota being reached), and this decision is made in response to a 'UPDATE_REQUEST' from the PCEF, the PCRF sends a CCA (Credit-Control-Answer) command. This CCA command must include the Session-Release-Cause AVP to inform the PCEF of the reason for the session termination, ensuring context-aware handling of the termination process by the PCEF.