question: What is the definition of complete mediation? option 1: Every access must be checked against the access control mechanism option 2: The design of a security mechanism should be open rather than secret option 3: A practice in which multiple privilege attributes are required to achieve access to a restricted resource option 4: Every process and every user of the system should operate using the least set of privileges necessary to perform the task option 5: The insertion of bits into gaps in a data stream to frustrate traffic analysis attempts 