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

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

Answer: B