Which of the following is an example of client-side virtualization?

A.
Compatibility mode on a program icon properties menu

B.
Running a DOS application on a Windows 7 32-bit operating system

C.
Cloud hosted office applications

D.
XP mode running in Windows 7 64-bit operating system

Explanation:
http://windows.microsoft.com/en-us/windows7/install-and-use-windows-xp-mode-inwindows-7