DNSSEC is used as a security extension to DNS lookup queries in order to ensure the authenticity and authoritativeness of hostname resolutions, in order to prevent spoofing and redirection of traffic. Although it is a very important concept to be employed for security practices, it is not used to secure or encrypt data transmissions. HTTPS is the most commonly used security mechanism for data communications between clients and websites and web services. IPSec is less commonly used, but is also intended to secure communications between servers. VPN is commonly used to secure traffic into a network area or subnet for developers and administrative users.

Explanation
Volume storage works as a virtual hard drive that is attached to a virtual machine. The operating system sees the volume the same as how a traditional drive on a physical server would be seen.

All the others are valid methods of data discovery; user-based is a red herring with no meaning.

With multitenancy, where different cloud customers all share the same physical systems and networks, data classification becomes even more important to ensure that the appropriate security controls are applied immediately to prevent any potential leakage or exposure to other customers. Portability refers to the ability to move easily from one cloud provider to another. Interoperability refers to the ability to reuse components and services for different uses. Reversibility refers to the ability of the cloud customer to quickly and completely remove all data and services from a cloud provider and to verify the removal.

Explanation/Reference:
Explanation:
Elasticity is the name for the benefit of cloud computing where resources can be apportioned as necessary to meet customer demand. Obfuscation is a technique to hide full raw datasets, either from personnel who do not have need to know or for use in testing. Mobility is not a term pertinent to the CBK.