You have two OSPF routers that are trying to form an adjacency. When you issue the command
show ospf neighbor, you see that one router is in the loading state and the other is in the full state.
Why are you seeing the router’s state as loading?

A.
The router does not know about the received LSA header and has transmitted a link-state
request.

B.
The router has finished transmitting, but is still receiving database information.

C.
The router is waiting for a start event.

D.
The router has established bidirectional communication with its peer.