As shown in the figure, SWA and SWB enable STP, and SWC does not enable STP. Initially, link 2 is not connected, and PCB can send data to PCA. If link 1 fails at this time, the maintenance personnel connect link 2. Which of the following statement about the recovery process of data transmission from PCB to PCA is (assuming that PCA will not actively send data) is correct?

As shown in the figure, SWA and SWB enable STP, and SWC does not enable STP. Initially, link 2 is not connected, and PCB can send data to PCA. If link 1 fails at this time, the maintenance personnel connect link 2. Which of the following statement about the recovery process of data transmission from PCB to PCA is (assuming that PCA will not actively send data) is correct?

A. Since the SWA link interruption will trigger the topology change process, the MAC address aging time of SWA and SWB will be shortened, so the service recovery takes 15 seconds by default.

B. Since SWB port EO/1 takes 30 seconds to enter the forwarding state by default, the service takes 30 seconds to recover by default.

C. When SWB port EO/1 enters the Forwarding state, it triggers the topology change process, so the service will eventually recover in the default time of 30+15=45 seconds.

D. Service recovery requires waiting for the MAC address of the SWC to age, so the default time is 300 seconds.

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Answer: D