A、With a network wide mask of 255.255.255.128, each interface does not require an IP address. B、With a network wide mask of 255.255.255.128, each interface does require an IP address on a unique IP subnet. C、With a network wide mask of 255.255.255.0, must be a Layer 2 device for the PCs to communicate with each other. D、With a network wide mask of 255.255.255.0, must be a Layer 3 device for the PCs to communicate with each other. E、With a network wide mask of 255.255.254.0, each interface does not require an IP address.