Your company has a Microsoft Hyper-V Server 2008 R2 environment. You manage the virtual environment by using Microsoft System Center Virtual Machine Manager （VMM） 2008 R2. You are creating a virtual test environment by installing two child partitions. The test environment must be completely isolated from all production servers. You need to ensure that the child partitions can communicate with each other. Which connection type should you configure？（）
- APrivate
- BInternal
- CExternal
- DDedicated host