Which option allows virtual machines to share the NIC of the host?

The option that allows virtual machines to share the Network Interface Card (NIC) of the host is bridging. Bridging is a network configuration that connects two network segments, which in this context refers to the virtual machines and the physical network. When bridging is configured, the virtual NICs of the virtual machines act as if they are directly connected to the physical network via the host's NIC. This allows them to communicate with other devices on the same network as if they were physical machines, sharing the host's NIC.

In contrast, while Virtual LANs (VLANs) do allow for network segmentation and can improve security and traffic management, they do not inherently facilitate the direct sharing of a NIC by virtual machines. NAT (Network Address Translation) typically enables virtual machines to access external networks while using private internal addresses, but it does not allow for direct sharing of the host's NIC for inbound traffic. Virtual NICs refer to the virtualized network adapters created for each virtual machine, which are essential for connectivity but are not a method of sharing the NIC directly; they still rely on bridging or other configurations to access the host NIC.