Under MAC, which of the following is true?

A.
All that is expressly permitted is forbidden.

B.
All that is not expressly permitted is forbidden.

C.
All that is not expressly permitted is not forbidden.

D.
None of the choices.

Explanation:
It is important to note that mandatory controls are prohibitive (i.e., all that is not
expressly permitted is forbidden), not permissive. Only within that context do
discretionary controls operate, prohibiting still more access with the same
exclusionary principle. In this type of control system decisions are based on privilege
(clearance) of subject (user) and sensitivity (classification) of object (file). It
requires labeling.