Confidentiality is defined as the property that ensures that only the intended recipient can access the data and nobody else. It is usually achieve using cryptogrphic methods, tools, and protocols.
Confidentiality supports the principle of “least privilege” by providing that only authorized individuals, processes, or systems should have access to information on a need-to-know basis. The level of access that an authorized individual should have is at the level necessary for them to do their job. In recent years, much press has been dedicated to the privacy of information and the need to protect it from individuals, who may be able to commit crimes by viewing the information. Identity theft is the act of assuming one’s identity through knowledge of confidential information obtained from various sources.
The following are incorrect answers: Capability is incorrect. Capability is relevant to access control. Capability-based security is a concept in the design of secure computing systems, one of the existing security models. A capability (known in some systems as a key) is a communicable, unforgeable token of authority. It refers to a value that references an object along with an associated set of access rights. A user program on a capability-based operating system must use a capability to access an object. Capability-based security refers to the principle of designing user programs such that they directly share capabilities with each other according to the principle of least privilege, and to the operating system infrastructure necessary to make such transactions efficient and secure.
Integrity is incorrect. Integrity protects information from unauthorized modification or loss. Availability is incorrect. Availability assures that information and services are available for use by authorized entities according to the service level objective.
Reference(s) used for this question: Hernandez CISSP, Steven (2012-12-21). Official (ISC)2 Guide to the CISSP CBK, Third Edition ((ISC)2 Press) (Kindle Locations 9345-9349). Auerbach Publications. Kindle Edition. http://en.wikipedia.org/wiki/Capability-based_security