What are three characteristics of the OSPF routing protocol？（）

• A、 It converges quickly.
• B、 OSPF is a classful routing protocol.
• C、 It uses cost to determine the best route.
• D、 It uses the DUAL algorithm to determine the best route.
• E、 OSPF routers send the complete routing table to all directly attached routers.
• F、 OSPF routers discover neighbors before exchanging routing information.