Which of the following port statuses may exist on an STP-enabled switch?

Comprehensive Explanation: In STP (Spanning Tree Protocol), ports can be in several states, including:

Discarding: The port is not forwarding traffic, either because it is in a blocking state or not participating in active forwarding.

Listening: The port is processing BPDUs and is preparing to transition to either the learning or forwarding state. No data frames are forwarded during this state.

Forwarding: The port is actively forwarding traffic as part of the active network topology.

The "Disabled" state is not part of the STP protocol but rather represents a port that is administratively shut down or not participating in the STP process.