The correct response is D. Physical access control regulates access to networking equipment, rooms, racks, and facilities. Examples include locks, badges, guards, cameras, mantraps, and visitor controls around wiring closets and data centers. For Cisco CCNA 200-301 v1.1, the important point is the mechanism, not a generic description of the technology. Access to file systems and specific networks is logical access control, not physical access control. When this appears in a network, the symptom normally confirms the answer: the route installed, the state selected, the packet forwarded, the wireless client behaviour, or the management workflow will follow this rule. That is why this answer is the best fit for the scenario and not just a plausible networking term.