Final answer:
A central authority determining file access is described by the Nondiscretionary access control model, where decisions are made based on organization-wide policies rather than individual preferences.
Step-by-step explanation:
The situation described in the question, where a central authority determines which files a user can access, is best described by a Nondiscretionary access control model. In a nondiscretionary access control model, the decisions regarding who has access to what resources are made by a central authority rather than by the owner of the resources. The system administrator or a similar position within an organization typically sets these policies based on roles or other criteria that apply across the board. This stands in contrast to discretionary access control (DAC), where individuals or owners of resources determine access, and access control lists (ACLs) or matrices that are more specific technical implementations of access control. The nondiscretionary model is usually used in situations where there is a need for standardized policies and a higher level of security control