单项选择题
A.10.1.207.17 B.172.163.20.15 C.192.166.100.1 D.192.1.203.31
A.255.255.250.0 B.255.255.252.0 C.255.255.254.0 D.255.255.255.0
A.202.100.73.0 B.202.100.70.0 C.202.100.128.0 D.202.100.72.0