Which of the following security models dictates that subjects can only access objects through applications?

The Biba model is an integrity model focused on preventing data from flowing from a higher integrity level to a lower integrity level ("no write down, no read up"), which is different from accessing objects through applications.

The Bell-LaPadula model is a confidentiality model focused on preventing unauthorized disclosure of information ("no read up, no write down"), which is not about access through applications.

The Clark-Wilson security model is an integrity model that enforces well-formed transactions. It dictates that subjects (users) cannot directly modify objects (data); instead, all modifications must occur through authorized programs or applications, ensuring data integrity by controlling the interface to data.

The Biba-Clark model is not a standard, recognized security model in this context; these models are typically distinct.