A user suspects that a recently installed program overwrote a Windows system file on the computer. Which of the following commands could be run to check and verify the system files？（）

A.CD
B.RD
C.MD
D.SD

A.Right-click the folder > Properties > Security tab > select the username from the list > Permissions > clear the box labeled Read > OK
B.Open the folder > Tool > Folder Options > General tab > Read-only > OK
C.Open the Command Prompt > type attrib r [drive：][path] > Enter
D.Open the Command Prompt > type attrib +r [drive：][path] > Enter
E.Right-click the folder > Properties > General tab > Attributes > select Read-only > OK

A.has offices where users who speak different languages share computers.
B.wants to maintain multiple operating systems.
C.has users who work remotely at home offices.
D.wants to deploy and maintain a single operating system standard.