At an organization, unauthorized users have been accessing network resources via unused network wall jacks. Which of the following would be used to stop unauthorized access?

Access control lists filter traffic based on IP addresses or protocols but do not prevent a device from physically connecting to an unused wall jack and gaining layer-2 network access.

Spanning Tree Protocol prevents switching loops by managing redundant paths and has no function related to authenticating or blocking devices from connecting to wall jack ports.

Port security lets administrators administratively disable unused switch ports and configure allowed MAC addresses on active ports, causing a violation response (shutdown, restrict, or protect) when an unauthorized device connects. This directly targets the physical layer vector of unused wall jacks providing uncontrolled network entry points.

Loop protection (an STP enhancement) guards against broadcast storms caused by switching loops and provides no capability to restrict which devices can physically plug into network ports.