Which of the following is NOT listed as a STP port state in the material?

• A. Listening
• B. Learning
• C. Transmit
• D. Disabled

Answer: (C)

STP port states describe how a switch port participates in the spanning-tree process to prevent loops. In classic STP, the possible states are Disabled, Blocking, Listening, Learning, and Forwarding. Transmit is not one of these states; it describes the action of sending frames, which happens when a port is in the Forwarding state but isn’t itself a separate state. Therefore, the option labeled Transmit isn’t a STP port state, while Listening, Learning, and Disabled are.