Explanation
DNSSEC is an extension of the normal DNS protocol that enables a system to verify the integrity of a DNS query resolution by signing it from the authoritative source and verifying the signing chain. It is not used for securing data transmissions or exchanges. HTTPS is the most common method for securing web service and data calls within a cloud, and TLS is the current standard for encrypting HTTPS traffic. VPNs are widely used for securing data transmissions and service access.

Explanation
All of these answers are actually correct, but A is the best answer, because it is the most general, includes the others, and is therefore the optimum choice. This is a good example of the type of question that can appear on the actual exam.

Explanation/Reference:
Explanation:
Reversibility is the cloud concept involving the ability for a cloud customer to remove all of its data and IT assets from a cloud provider. Also, processes and agreements would be in place with the cloud provider that ensure all removals have been completed fully within the agreed upon timeframe. Portability refers to the ability to easily move between different cloud providers and not be locked into a specific one.
Removability and extraction are both provided as terms similar to reversibility, but neither is the official term or concept.

The Simple Object Access Protocol (SOAP) protocol only supports the Extensible Markup Language (XML) data format. Although the other options are all data formats or data structures, they are not supported by SOAP.