An OSPF network has been designed with multiple areas to improve scalability. Which two statements are true? (Choose two.)

A.
Each router in the OSPF network runs the shortest-path-first algorithm to determine paths through the network.

B.
The Area Border Router for each area runs the shortest-path-first algorithm and floods its results through the area.

C.
Each area must have at least one link connecting it to each of the other areas of the OSPF network.

D.
OSPF provides loop-free routing within an OSPF routing domain, but does not guarantee symmetrical routing.