You have a portable computer that runs Windows 7. The computer is joined to a domain. Multiple users logon to the computer. You need to prevent the computer from displaying the username of the last user whologged on. What should you do？（）

A. From Control Panel， modify the User Profiles settings.
B. From Control Panel， modify the Personalization settings.
C. From the local computer policy， add a policy template.
D. From the local computer policy， modify the local security policy.