Final answer:
Hosts on a switched local network receiving and processing a message from a single host are part of a Local Area Network (LAN). This type of network allows for direct communication within a limited geographical area.
Step-by-step explanation:
When a host on a local network sends a message that all other hosts receive and process, these hosts are part of a Local Area Network (LAN). LANs are networks in a limited area, like an office building or school, allowing computers and devices within this area to communicate and share data directly through physical or wireless connections. The other options, such as Intranet, Internet, and WAN, represent different types of networks. An Intranet is a private network within an organization, the Internet is a global network connecting millions of private, public, academic, business, and government networks, and a WAN (Wide Area Network) covers a broader area than a LAN, potentially connecting networks across cities, states, or even countries.