Private VLANs (PVLANs) are used to segment devices on the same subnet and switch so they cannot communicate with each other, while still accessing a shared resource like a router or gateway. This is often used in shared hosting or DMZ environments.
A). ACLs (Access Control Lists) control traffic between networks, not within the same VLAN.
B). Trunking carries multiple VLANs between switches but does not isolate devices.
C). Port security limits MAC addresses per port but doesn't isolate communication between ports.
# Reference:
CompTIA Network+ N10-009 Official Objectives: 3.4 - Compare and contrast access control methods.