1. [单选题]以下特殊区域中哪一个没有自动下发缺省路由（）
A. 末梢区域
B. 完全末梢区域
C. NSSA区域
D. 完全NSSA区域
2. [单选题]下列对RIP的配置中，合法的命令是（）
A. router rip 100 network 10.12.0.0
B. router rip 100 network 10.0.0.0
C. router rip network 10.12.0.0
D. router rip 100 network 10.0.0.0
3. [单选题]When is a switched network that is running the Spanning Tree Protocol considered to be fully converged?
A. when all switches have the same BID as the root switch
B. when all switches have received the MAC address of each neighboring switch
C. when every enabled switch port has been assigned a unique identifier
D. when every operating switch port is in either the blocking or forwarding state
E. when all switches are in either client, server, or transparent mode
