单项选择题
A.物理层 B.数据链路层 C.网络层 D.应用层
A.(26-m)×24 B.(26-m)×(24-1) C.(24-m)×26 D.(24-m)×(26-1)
A.1111111 1.1000......00 B.0011111 1.0111......01 C.1000001 0.1111......01 D.0111111 0.1000......10