When will BLP consider the information flow that occurs?

A.
When a subject alters on object.

B.
When a subject accesses an object.

C.
When a subject observer an object.

D.
All of the choices.

Explanation:
Bell-LaPadula is a state machine model capturing confidentiality aspects of access control. Access
permissions are defined through an Access Control matrix and through a partial ordering of security
levels. Security policies prevent information flowing downwards from a high security level to a low
security level. BLP only considers the information flow that occurs when a subject observes or alters
an object.