In Discretionary Access Control the subject has authority, within certain limitations, 

Answer options:

A. but he is not permitted to specify what objects can be accessible and so we need to get an independent third party to specify what objects can be accessible.
B. to specify what objects can be accessible.
C. to specify on a aggregate basis without understanding what objects can be accessible.
D. to specify in full detail what objects can be accessible.

B

With Discretionary Access Control, the subject has authority, within certain limitations, to specify what objects can be accessible. For example, access control lists can be used. This type of access control is used in local, dynamic situations where the subjects must have the discretion to specify what resources certain users are permitted to access. When a user, within certain limitations, has the right to alter the access control to certain objects, this is termed as user-directed discretionary access control. In some instances, a hybrid approach is used, which combines the features of user-based and identity-based discretionary access control. References: KRUTZ, Ronald L. & VINES, Russel
D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 33. and HARRIS, Shon, All-In-One CISSP Certification Exam Guide 5th Edition, McGraw-Hill/Osborne, 2010, Chapter 4: Access Control (page 210-211).