Regarding the description of OSPF neighbor relationship and adjacency relationship, which of the following statement is true?

Regarding the description of OSPF neighbor relationship and adjacency relationship, which of the following statement is true?
A . The adjacency is maintenance by the DD message of OSPF
B . OSPF routers must establish an adjacency before exchanging Hello packets
C . Neighbor relationship is a relationship selected from adjacency relationships for the purpose of exchanging routing information
D . Not all neighbor relationships can become adjacency relationships

View Answer

Answer: D