Consider the following output from a Cisco Catalyst switch: Which of the following answers is true about this switch?

Consider the following output from a Cisco Catalyst switch:

SW1# show mac address-table dynamic
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
1 02AA.AAAA.AAAA DYNAMIC Gi0/1
1 02BB.BBBB.BBBB DYNAMIC Gi0/2
1 02CC.CCCC.CCCC DYNAMIC Gi0/3
Total Mac Addresses for this criterion: 3

Which of the following answers is true about this switch?

• The output proves that port Gi0/2 connects directly to a device that uses address 02BB.BBBB.BBBB.
• The switch has learned three MAC addresses since the switch powered on.
• The three listed MAC addresses were learned based on the destination MAC address of frames forwarded by the switch.
• 02CC.CCCC.CCCC was learned from the source MAC address of a frame that entered port Gi0/3.

Explanation: For the correct answer, each entry lists the learned MAC address. By definition, dynamically learned MAC addresses are learned by looking at the source MAC address of received frames. (That fact rules out one of the incorrect answers as well.)
The show mac address-table dynamic command lists the current list of MAC table entries, with three known entries at the point at which the command output was gathered. The counter in the last line of output lists the number of current entries, not the total number of learned MAC addresses since the last reboot. For instance, the switch could have learned other MAC addresses whose entries timed out from the MAC address table.
Finally, the answer that claims that port Gi0/2 connects directly to a device with a particular MAC address may or may not be true. That port could connect to another switch, and another, and so on, with one of those switches connecting to the device that uses the listed MAC address.