Virtual Network Manager (available from the Hyper-V Manager snap-in) offers three types of virtual networks
that you can use to define various networking topologies for virtual machines and the virtualization server.
Which type of virtual network is isolated from all external network traffic on the virtualization server, as well any
network traffic between the management operating system and the external network.
A.
Internal virtual network
B.
Private virtual network
C.
External virtual network
D.
None of these
Correct. https://technet.microsoft.com/en-us/library/cc816585%28v=ws.10%29.aspx?f=255&MSPPError=-2147217396
Private virtual networks. Use this type when you want to allow communication only between virtual machines on the same virtualization server. A private virtual network is not bound to a physical network adapter. A private virtual network is isolated from all external network traffic on the virtualization server, as well any network traffic between the management operating system and the external network. This type of network is useful when you need to create an isolated networking environment, such as an isolated test domain.