Question: In a PCC architecture, when the PCRF receives an `APPLICATION_START` Event-Trigger within the Application-Detection-Information AVP, which of the following AVPs must also be included if Flow-Information is deducible and present?
Option 1: Mute-Notification AVP
Option 2: TDF-Application-Instance-Identifier AVP and Flow-Description AVP within Flow-Information AVP
Option 3: Charging-Rule-Definition AVP
Option 4: Event-Trigger AVP alone
Explanation: According to the specifications, when an `APPLICATION_START` event is triggered and the Flow-Information AVP is included (if deducible), it must contain the Flow-Description AVP. Additionally, this setup mandates the presence of the TDF-Application-Instance-Identifier AVP, ensuring comprehensive reporting for precise policy and charging control.