A.3 B.7 C.8 D.9
A.1024 B.2046 C.4094 D.4096
A.route ip 172.0.0.0 255.0.0.0s0 B.ip route 0.0.0.00.0.0.0 172.16.20.1 C.ip route 0.0.0.0255.255.255.255 172.16.20.1 D.route ip 0.0.0.0255.255.255.0 172.16.10.1150