Which of the following statements pertaining to the security kernel is incorrect?

A.
It is made up of mechanisms that fall under the TCB and implements and enforces the reference
monitor concept.

B.
It must provide isolation for the processes carrying out the reference monitor concept and they
must be tamperproof

C.
It must be small enough to be able to be tested and verified in a complete and comprehensive
manner

D.
Is an access control concept, not an actual physical component