You manage your virtual environment by using Microsoft System Center Virtual Machine Manager （VMM） 2008 R2 running on the internal network. You have several host servers in a perimeter network （also known as DMZ）. You are installing VMM agents on the host servers. You need to ensure that the agents can communicate with the VMM server. Which two elements should you configure？（）

• A、a port number
• B、an encryption key
• C、the VMM server name
• D、the URL of the VMM Self-Service Portal