Final answer:
In social networks, a e) 'structural hole' is the term for the critical link between individuals or entire groups, where an actor bridges disconnected segments of the network.
Step-by-step explanation:
The term that describes relationships in social networks in which one actor is the critical link between individuals or entire groups is known as a structural hole. This concept highlights the role of specific individuals or nodes as crucial connections in larger social or professional networks that would otherwise be segmented or disjointed. These individuals essentially bridge the gap between separate cliques or clusters, allowing for the flow of information and resources across the entire network, which is instrumental for group cohesion, knowledge sharing, and social capital.