What is 'MAC address table aging' on a switch, and what is the default aging time on most enterprise switches?

• A.MAC address aging permanently removes inactive MACs and requires manual re-entry
• B.The MAC address table (CAM table) has a configurable aging timer (default 300 seconds on most Cisco switches); if no frame with a particular source MAC is seen for 300 seconds, the entry is removed; on the next frame for that MAC as a destination, the switch floods it as unknown unicast until the MAC is re-learned from a new source frame
• C.MAC aging is disabled by default and must be manually enabled with a CLI command
• D.The MAC aging timer is the same as the ARP cache timeout and cannot be configured separately