单项选择题

A.Upgrade all of the Windows Vista computers to Windows 7.
B.Upgrade all of the Windows Vista computers to Windows Vista Service Pack 2 (SP2).
C.Assign the Microsoft Windows Rights Management Services (RMS) Client Service Pack 2 (SP2) to all  users by using a Software Installation extension of Group Policy.
D.Assign the Microsoft Windows Rights Management Services (RMS) Client Service Pack 2 (SP2) to all  computers by using a Software Installation extension of Group Policy.