What does it mean to "prune" a VLAN?

The correct answer describes the process of pruning a VLAN as removing it from trunk ports to optimize bandwidth usage and improve performance. In network environments, trunks are links that carry multiple VLANs between switches. Not all VLANs need to be active on all trunk links. By pruning a VLAN, network administrators can limit the propagation of VLANs only to those trunk ports that require them, thereby reducing unnecessary traffic across the network. This helps to conserve bandwidth and enhances overall network efficiency, as less traffic means less load on the switches and a reduced chance of congestion.

The key concept here is that pruning is a strategic operation aimed at refining and optimizing the network's performance, rather than a permanent deletion or other alterations of VLAN configurations that the other options imply. For instance, simply deleting a VLAN or disabling functionality could disrupt the network, highlighting why pruning is a more tactical approach to managing VLANs for better resource utilization.