What is the difference between mandatory access control (MAC) and discretionary access control (DAC)?

A.	MAC is controlled by the discretion of the owner and DAC is controlled by an administrator
B.	MAC is the strictest of all levels of control and DAC is object-based access
C.	DAC is controlled by the operating system and MAC is controlled by an administrator
D.	DAC is the strictest of all levels of control and MAC is object-based access