When is a switched network that is running the Spanning Tree Protocol considered to be fully converged?

D
解析：Explanation:States of the Spanning Tree Protocol:Blocking A blocked port won't forward frames; it just listens to BPDUs. All ports are in blocking state by default when the switch is powered up. The purpose of the blocking state is to prevent the use of looped paths.Listening The port listens to BPDUs to make sure no loops occur on the network before passing data frames. A port in listening state prepares to forward data frames without populating the MAC address table.Learning The switch port listens to BPDUs and learns all the paths in the switched network. A port in learning state populates the MAC address table but doesn't forward data frames.Forwarding The port sends and receives all data frames on the bridged port.Disabled A port in the disabled state does not participate in the frame. forwarding or STP. A port in the disabled state is virtually nonoperational. In Blocking States, all ports are in blocking state. The purpose of the blocking state is to prevent the use of looped paths. The forward state sends and receives the all data frames in a loop free network. So these two states are considered to be fully converged.