Which two actions should you perform?

You support Microsoft Lync Server 2013 servers in your customer’s network. The network is isolated from Internet with a firewall.
Users report voice and video communication problems while communicating with external participants.
You need to verify port availability for audio/video communication on the Edge Server. Which two actions should you perform? (Each correct answer presents part of the solution. Choose two.)
A. Check TCP port 443.
B. Check UDP port 3478.
C. Check TCP port 4443.
D. Check TCP port 5061.
E. Check TCP port 8057.