Final answer:
The private network using internet technologies and restricted to certain hosts is known as an intranet. In the context of broadcasting, a local station airing national network programming is called an affiliate. option a is the correct answer.
Step-by-step explanation:
The network that uses internet technologies, but limits data and services to hosts connected to the private network, is called a(n) intranet. In contrast, an extranet also uses internet technologies but extends access to a certain business's resources to external partners or vendors. An internetwork is a collection of multiple networks, interconnected with routers and other devices, while a subnet denotes a subdivided network segment within an intranet or internet.
However, if we were to answer a different question embedded within your request: A local station that broadcasts national network programming is referred to as an affiliate. This is distinct from a cable station, which refers to television networks distributed through cable television systems, and from digital which typically refers to the format in which signals are encoded. A network, in this context, usually refers to the core broadcaster providing content to the affiliates.