Which command displays users currently in the local authentication database?

The command that displays users currently in the local authentication database is "show users." This command specifically provides a list of all users configured in the device's local database, which is crucial for network administrators to verify authentication settings and monitor access to the network.

The other commands listed serve different purposes: "show ip users" is not a standard command in Cisco IOS for displaying local users; "show running-config" displays the entire current configuration of the device, including various settings but not specifically the local user database; and "display users" is not a recognized command in Cisco IOS. Therefore, "show users" is the correct choice for viewing the users in the local authentication database.