Which statement is true about a distributed call control environment and the processing of dialed digits from an IP phone？（）

• A、The router that is directly connected to the IP phone will look up the called number in its call routing table.
• B、The router that is directly connected to the IP phone will inform its call agent when a service request is detected.
• C、When the IP phone is picked up，the IP phone initiates the service request.
• D、The directly connected router passes the collected digits to its call agent，and the call agent looks up in its call-routing table the called number.