Anonymization is a type of masking, where indirect identifiers are removed from a data set to prevent the mapping back of data to an individual. Although masking refers to the overall approach of covering sensitive data, anonymization is the best answer here because it is more specific to exactly what is being asked.
Tokenization involves the replacement of sensitive data with a key value that can be matched back to the real value. However, it is not focused on indirect identifiers or preventing the matching to an individual. Encryption refers to the overall process of protecting data via key pairs and protecting confidentiality.

Explanation
Portability is the ease with which a service or application can be moved between different cloud providers.
Maintaining portability gives an organization great flexibility between cloud providers and the ability to shop for better deals or offerings.

Explanation
The Uptime Institute publishes the most commonly used and widely known standard on data center tiers and topologies. It is based on a series of four tiers, with each progressive increase in number representing more stringent, reliable, and redundant systems for security, connectivity, fault tolerance, redundancy, and cooling.

Explanation
IaaS entails the cloud customer installing and maintaining the OS, programs, and data; PaaS has the customer installing programs and data; in SaaS, the customer only uploads data. In a community cloud, data and device owners are distributed.