1. [单选题]RIP协议负载均衡的路径数量为（）
A. 无限制
B. 最多4条
C. 最多5条
D. 最多6条
2. [单选题]After logging into a router and typing in a few show commands, you press the up arrow key. What will this do?
A. It will recall the previous command line
B. It will move the cursor one line up
C. It will redisplay the current command line
D. It will capitalize the command line
E. None of the above
3. [单选题]TCP23是（）协议端口号；UDP69是（）端口号；TCP80是（）端口号。
A. TELNET FTP HTTP
B. FTPT FTP HTTP
C. TELNET TFTP HTTP
D. TELNET DNS HTTP
