What is the default behavior of a Layer 2 switch when a frame with an unknown destination MAC address is received? 

Answer options:

A. The Layer 2 switch forwards the packet and adds the destination MAC address to its MAC address table.
B. The Layer 2 switch sends a copy of a packet to CPU for destination MAC address learning.
C. The Layer 2 switch floods packets to all ports except the receiving port in the given VLAN.
D. The Layer 2 switch drops the received frame.

C

If the destination MAC address is not in the CAM table (unknown destination MAC address), the switch sends the frame out all other ports that are in the same VLAN as the received frame. This is called flooding. It does not flood the frame out the same port on which the frame was received.