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.

A.Router1 will strip off the source MAC address and replace it with the MAC address 0000.0c36.6965.
B.Router1 will strip off the source IP address and replace it with the IP address 192.168.40.1.
C.Router1 will strip off the destination MAC address and replace it with the MAC address 0000.0c07.4320.
D. Router1 will strip off the destination IP address and replace it with the IP address of 192.168.40.1.
E.Router1 will forward the data packet out interface FastEthernet0/1.
F.Router1 will forward the data packet out interface FastEthernet0/2.