Non-Discretionary Access Control. A central authority determines what subjects can have access to certain objects based on organizational security policy. The access controls may be based on the individual's role in the organization (role-based) or the subject's responsibilities and duties (task-based). Pg. 33 Krutz: The CISSP Prep Guide.

A Sensitivity label must contain at least one classification and one category set.
Category set and Compartment set are synonyms, they mean the same thing. The sensitivity label
must contain at least one Classification and at least one Category. It is common in some
environments for a single item to belong to multiple categories. The list of all the categories to
which an item belongs is called a compartment set or category set.
The following answers are incorrect:
the item's classification. Is incorrect because you need a category set as well.
the item's category. Is incorrect because category set and classification would be both be
required.
The item's need to know. Is incorrect because there is no such thing. The need to know is
indicated by the catergories the object belongs to. This is NOT the best answer.
Reference(s) used for this question:
OIG CBK, Access Control (pages 186 - 188)
AIO, 3rd Edition, Access Control (pages 162 - 163)
AIO, 4th Edittion, Access Control, pp 212-214.
Wikipedia - http://en.wikipedia.org/wiki/Mandatory_Access_Control

The correct answer is "Specific servers and locations cannot be secured". Kerberos requires that centralized servers implementing the trusted authentication mechanism must be secured.

Explanation/Reference:
Explanation:
DNS translates domain names into IP addresses, which enables us to use domain names instead of IP addresses.
Incorrect Answers:
A: RIP is a routing protocol. A routing protocol forwards routing information between routers, but does make it easier for users to communicate.
B: IGRP is a routing protocol. A routing protocol forwards routing information between routers, but does make it easier for users to communicate.
D: OSPF is a routing protocol. A routing protocol forwards routing information between routers, but does make it easier for users to communicate.
References:
Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, p. 599

This is a well known issue knew by many programmers, since the operating system is allowing the executables to be used by many users in different sessions at the same time, and there is not refreshing every certain time, there will be a disclosure of residual data. To fix this we need to get sure that objects are refreshed frequently, for added security its better an OS that does not allow the use of an executable object by many users at the same time.