A certain SMC video conferencing system site hopes to deploy the conference system with the least license resources for public and private network single-select traversal traffic, and plans to have a DMZ area. Which of the following networking types best meets the needs of the site?

A certain SMC video conferencing system site hopes to deploy the conference system with the least license resources for public and private network single-select traversal traffic, and plans to have a DMZ area. Which of the following networking types best meets the needs of the site?
A . Neighbor approach
B . SIP proxy method
C . Back-to-back method
D . Cross-server and cross-client methods

Answer: D