Refer to the exhibit． When running OSPF, What would cause router A not to form an adjacency with router B?

A、 The loopback addresses are on different subnets．
B、 The value of the dead timers on the router are different．
C、 Route summarization is enabled on both routers．
D、 The process indentifier on router A is different than the process identifier on router

【正确答案】 B

【答案解析】考点：考查OSPF邻居建立的条件。
区域ID，hello周期，网段，认证等。
A：loopback地址不同网段，错误
B：hello的死亡时间不一样，正确
C：开启了路由汇总，错误。这个没关系
D：两端的路由进程不一致。错误。