The * (star) property of the Biba model states that:

A.
Subjects cannot read from a higher level of integrity relative to their
level of integrity.

B.
Subjects cannot write to a higher level of integrity relative to their
level of integrity.

C.
Subjects cannot read from a lower level of integrity relative to their
level of integrity.

D.
Subjects cannot write to a lower level of integrity relative to their level
of integrity.