单项选择题

A. route.exe add -p 192.168.0.0 mask 255.255.248.0 172.31.255.254
B. route.exe add -p 192.168.12.0 mask 255.255.252.0 172.31.255.254
C. route.exe add -p 192.168.8.0 mask 255.255.252.0 172.31.255.254
D. route.exe add -p 192.168.12.0 mask 255.255.255.0 172.31.255.254