CompTIA Security+ Exam Prep

Answer: C - A reference monitor is an abstract machine that mediates all access subjects to objects. This is to ensure that the subjects have the necessary access rights and to protect the objects from unauthorized access and destructive modification. For a system to achieve a higher level of trust, it must require subjects (programs, users, or processes) to be fully authorized prior to accessing an object (file, program, or resource). A subject must not be allowed to use a requested resource until the subject has proven it has been granted access privileges to use the requested objects. The reference monitor is an access control concept, not an actual physical component.