单项选择题 Refer to the exhibit. A network administrator configures a new router and enters the copy startup-config running-config on the router. The network administrator powers down the router and sets it up at a remote location. When the router starts, it enter the system configuration dialog as shown. What is the caust of the problem?（）

多项选择题 Which statements describe the routing protocol OSPF?（）

多项选择题 What information does a router running a link-state protocol use to build and maintain its topological database? （）