What is a VLAN, and why is it used?

A VLAN, or Virtual Local Area Network, is a technology that allows for the segmentation of a single physical network into multiple logical networks. Option C is correct because VLANs enable administrators to group devices that are on different physical LANs into the same broadcast domain. This segmentation improves network management by allowing for better traffic control, enhanced security, and the ability to apply policies to specific groups of devices.

By using VLANs, an organization can reduce the size of broadcast domains, which can decrease unnecessary traffic and improve overall network efficiency. Additionally, VLANs can enhance security by isolating sensitive information and limiting access to that data only to those devices assigned to the specific VLAN. This is particularly useful in environments where different departments or functions require varied levels of access to network resources without needing to physically separate devices.

In contrast, other options describe incorrect interpretations of VLANs or other networking concepts. For example, the first option claims it improves physical network speed, which is misleading because while VLANs can enhance network efficiency, they do not inherently improve physical speed; that depends on other factors such as the underlying infrastructure. The second option incorrectly describes VLANs as "Very Large Area Networks," which fundamentally misrepresents what a VLAN is and its application. Lastly, the fourth