In OSPF (Open Shortest Path First), routers exchange database information in multiple stages.
* ExStart State (Correct Answer):
* The Master/Slave relationship is determined in this phase.
* The router with the higher Router ID becomes the Master, and the other becomes the Slave.
* The Master initiates the exchange of Database Description (DD) packets.
* 2-way State (Incorrect): This state is reached when two routers recognize each other as neighbors but have not started database exchange.
* Exchange State (Incorrect): The actual exchange of DD packets happens in this state, but the Master
/Slave roles are already established in ExStart.
* Full State (Incorrect): This is the final state where routers have synchronized their link-state databases.
Thus, the correct answer is D (ExStart).
Reference:Huawei HCIA-Datacom Official Documentation - OSPF Neighbor State Machine

* Direct Route (C): This has the highest priority because it represents networks directly connected to a router's interfaces.
* Static Route (B): These are manually configured but have lower priority than direct routes.
* OSPF Route (D): OSPF dynamically learns routes and assigns them based on cost, but it has lower priority than direct and static routes.
* RIP Route (A): RIP has the lowest priority due to its high administrative distance (120).
Priority order (from highest to lowest):Direct Route > Static Route > OSPF Route > RIP Route.
Thus, the correct answer is C (Direct Route).
Reference: HCIA-Datacom Study Guide, Routing Basics Section.