Which best describes the *-integrity axiom?

A.
No write up in the Biba model
B.
No read down in the Biba model
C.
No write down in the Bell-LaPadula model
D.
No read up in the Bell-LaPadula model
Explanation:
A: The *-integrity axiom (or star integrity axiom) indicates that a subject of a lower integrity level cannot write to an object of a higher integrity level. This rule is put into place to protect the integrity of the data that resides at the higher level.