When a router undergoes the exchange protocol within OSPF, in what order does it pass through each state?（）

A.a command that is set once and affects the entire router
B.a command that is implemented in all foreign and domestic IOS versions
C.a command that is universal in application and supports all protocols
D.a command that is available in every release of IOS, regardless of the version or deployment status
E.a command that can be entered in any configuration mode

A.the operation of VTP
B.a method of VLAN trunking
C.an approach to wireless LAN communication
D.the process for root bridge selection
E.VLAN pruning vlan