What command is used to verify the configuration of VLANs on a switch?

Using the command "show vlan brief" provides a summarized view of all VLANs configured on a switch. This command allows network administrators to quickly see the VLAN ID, the associated name, and the ports that belong to each VLAN. This makes it particularly useful for verifying whether the desired VLANs are configured correctly and to confirm that the right switch ports are assigned to those VLANs.

In contrast, the other choices do not serve this specific purpose. "Show vlan configuration" and "show vlan status" are not standard commands in Cisco IOS for VLAN verification, and "show port status" focuses more on the status of individual switch ports rather than the VLANs themselves. Therefore, "show vlan brief" is the most appropriate command to use when needing to check VLAN configurations on a switch.