While you are troubleshooting network performance issues， you notice that a switch is periodically flooding all unicast traffic. Further investigation reveals that periodically the switch is also having spikes in CPU utilization， causing the MAC address table to be flushed and relearned. What is the most likely cause of this issue？（）

• A、a routing protocol that is flooding updates
• B、a flapping port that is generating BPDUs with the TCN bit set
• C、STP is not running on the switch
• D、a user that is downloading the output of the show-tech command
• E、a corrupted switch CAM table