Which of the following solutions provides the most flexibility when testing new security controls
prior to implementation?

A.
Trusted OS

B.
Host software baselining

C.
OS hardening

D.
Virtualization

Explanation:
Virtualization is used to host one or more operating systems in the memory of a single host
computer and allows multiple operating systems to run simultaneously on the same hardware.
Virtualization offers the flexibility of quickly and easily making backups of entire virtual systems,
and quickly recovering the virtual system when errors occur. Furthermore, malicious code
compromises of virtual systems rarely affect the host system, which allows for safer testing and
experimentation.