Which of the following attacks can be avoided by using the built-in port security feature of Cisco switches?

The correct answer is D. MAC flooding.

Explanation: Port security on Cisco switches can prevent MAC flooding attacks by limiting the number of MAC addresses that can be learned on a port. When the limit is reached, the switch can take action, such as shutting down the port or restricting further MAC address learning, which protects against attackers attempting to inundate the switch with spoofed MAC addresses to disrupt network operations.

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