单项选择题
A. user@router# system delete configuration rescue
B. user@router> request system configuration rescue delete
C. user@router# delete rescue configuration
D. user@router> file delete rescue-configuration
单项选择题 Using the routing table shown in the exhibit, what will be the next-hop IP address used for destination IP address 192.168.1.1? （）
单项选择题 You have been asked to use a 23-bit network mask to segment the network block 209.18.12.0, How many usable host address will there e per subnet?（）
单项选择题 Which statement is true about the routing table?（）