Refer to the exhibit. An administrator is troubleshooting a problem in which some outbound calls from an internal network to the Internet telephony service provider are not getting connected, but some others connect successfully. The firewall team found that some call attempts on port 5060 came from an unrecognized IP that has not been defined in the firewall rule. What should the administrator configure in the Cisco Unified Border Element to fix this issue?
A. use of port 5061 for SIP secure
B. access list allowing the firewall IP
C. bind signaling and media to the loopback interface
D. ip prefix-list to filter the unwanted IP address
