Final answer:
The IT infrastructure links to a WAN and the Internet in the LAN-to-WAN Domain, involving devices that manage traffic between networks.
Step-by-step explanation:
The IT infrastructure connects to a wide area network (WAN) and the Internet in the D. LAN-to-WAN Domain. This domain encompasses all the technology required to link local area networks (LANs) with WANs. It includes networking devices such as routers, switches, and firewalls that manage the traffic between the internal networks and external networks like the Internet.