An administrator needs to connect a router in one building to a router in another using Ethernet. Each router is connected to a managed switch and the switches are connected to each other via a…

Assigning all ports to a non-default VLAN segments traffic but does not prevent an unauthorized device from physically connecting to and communicating within that VLAN.

VTP synchronizes VLAN configuration across switches to reduce administrative overhead but has no mechanism to authenticate or restrict which devices can plug into switch ports.

Running DHCP on only one router limits IP address issuance but an unauthorized device can still gain access by assigning itself a static IP address.

Port security is a switch feature that limits valid MAC addresses on a per-port basis and triggers a configurable violation action (restrict, protect, or shutdown) when an unknown device connects. It is the only option listed that actively authenticates and restricts physical device connections at the switch level, addressing the scenario directly.