A.Traffic forwarded from R2 to or through R1 will continue to be forwarded based on the forwarding table state at the time of the reload.
B.R2 will continue to forward traffic to R1， but R1 will drop the traffic because its neighbor adjacency with R2 has failed.
C.R2 will continue forwarding traffic to and through R1， but R1 will drop this traffic because it is not capable of maintaining its forwarding state.
D.All the traffic R2 is forwarding to or through R1 will be dropped while OSPF rebuilds its neighbor adjacency and forwarding tables.

A.It ensures that BPDUs sent by the root bridge are forwarded in a timely manner
B.It enforces the root bridge placement in the network
C.It ensures that all ports receiving BPDUs from the root bridge are in the forwarding state.
D.It ensures that the bridge is elected as root bridge in the network.