An IEEE 802.1D port goes through four states when transitioning to the forwarding state. What is the correct order?

A) Blocking, learning, listening, forwarding
B) Learning, listening, blocking, forwarding
C) Blocking, listening, learning, forwarding
D) Listening, blocking, learning, forwarding

C
Explanation: If a port needs to transition to the forwarding state, it does not do so immediately. Rather, it transitions through the following states:
• Blocking: The port remains in the blocking state for 20 seconds by default. During this time, the nondesignated port evaluates BPDUs in an attempt to determine its role in the spanning tree.
• Listening: The port moves from the blocking state to the listening state and remains in this state for 15 seconds by default. During this time, the port sources BPDUs, which inform adjacent switches of the port's intent to forward data.
• Learning: The port moves from the listening state to the learning state and remains in this state for 15 seconds by default. During this time, the port begins to add entries to its MAC address table.
• Forwarding: The port moves from the learning state to the forwarding state and begins to forward frames.