Enabling Inter-VLAN Communication

A

The correct answer is A: a router with subinterfaces configured on the physical interface that is connected to the switch.

Explanation: A VLAN (Virtual Local Area Network) is a logical group of devices that are configured to communicate with each other as if they were on the same physical LAN (Local Area Network), even though they may be physically located on different segments of the network.

When hosts are on the same VLAN, they can communicate with each other using the MAC addresses of the devices. However, hosts on different VLANs cannot communicate with each other by default, because VLANs are separate broadcast domains. Therefore, to allow communication between VLANs, a router is required to route traffic between the VLANs.

Option B, "a router with an IP address on the physical interface connected to the switch," is not a correct answer because a router must have subinterfaces configured on the physical interface to communicate with multiple VLANs. Each subinterface is associated with a different VLAN, and each VLAN has a unique IP address.

Option C, "a switch with an access link that is configured between the switches," is also not a correct answer because an access link is used to connect an end device, such as a computer or printer, to a switch port on a single VLAN. It does not provide connectivity between VLANs.

Option D, "a switch with a trunk link that is configured between the switches," is also not a correct answer because a trunk link is used to carry traffic between multiple VLANs on a single physical link. It does not provide connectivity between VLANs on different switches.

Therefore, the correct answer is A: a router with subinterfaces configured on the physical interface that is connected to the switch.