A、Router R1 is waiting for a reply from the neighbor 10.1.2.1 to the hello message sent out inquiring for a second successor to network 10.6.1.0/24. B、Router R1 can send traffic destined for network 10.6.1.0/24 out of interface FastEthernet0/0. C、Router R1 is waiting for a reply from the neighb or 10.1.2.1 to the hello message sent out before it declares the neighbor unreachable. D、Router R1 is waiting for a reply from the neighbor 10.1.2.1 in response to the query sent out about network 10.6.1.0/24.