Which of these does the taxonomy NOT list as an example of an actor?

1. The volume gives a bulleted list of example actors: sensors, applications, software agents, individuals, organizations, hardware resources, and service abstractions. 2. Software agents, service abstractions and hardware resources are all on that list, so none of them can be the answer. 3. Semantic metadata is not, and could not be. The volume defines actors as things that perform roles, stating that "System development actors can represent individuals, organizations, software, or hardware." 4. Metadata is data about data. It is acted upon rather than acting so it fails the definition even though it appears elsewhere in the framework as the thing that makes automated data fusion possible. 5. What is striking about the real list is how wide it is. A sensor and an organisation sit in the same list, which is the point: the taxonomy is about function, not about scale or kind. _Source: NIST SP 1500-2r2 "NIST Big Data Interoperability Framework: Volume 2, Big Data Taxonomies" (Nov 2019), p.6 section 2.1 "Actors and Roles"_