Which of the following access control models requires defining classification for objects? 

Answer options:

A. Role-based access control
B. Discretionary access control
C. Identity-based access control
D. Mandatory access control

D

With mandatory access control (MAC), the authorization of a subject`s access to an object is dependant upon labels, which indicate the subject`s clearance, and classification of objects. The Following answers were incorrect: Identity-based Access Control is a type of Discretionary Access Control (DAC), they are synonymous. Role Based Access Control (RBAC) and Rule Based Access Control (RuBAC or RBAC) are types of Non Discretionary Access Control (NDAC). Tip: When you have two answers that are synonymous they are not the right choice for sure. There is only one access control model that makes use of Label, Clearances, and Categories, it is Mandatory Access Control, none of the other one makes use of those items. Reference(s) used for this question: KRUTZ, Ronald L. & VINES, Russel
D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 2: Access control systems (page 33).