单项选择题
A.128 B.64 C.48 D.32
A.202.17.0.0/13 B.202.17.0.0/24 C.202.17.0.0/18 D.202.17.8.0/20
A.222.125.80.128 B.222.125.80.190 C.222.125.80.192 D.222.125.80.254