Your network contains an Active Directory domain.     You have a server named Server1 that runs Windows Server 2008 R2. Server1 is an enterprise root certification authority （CA）.   You have a client computer named Computer1 that runs Windows 7. You enable automatic  certificate enrollment for all client computers that run Windows 7. You need to verify that the  Windows 7 client computers can automatically enroll for certificates.     Which command should you run on Computer1（）

• A、certreq.exe -retrieve
• B、certreq.exe -submit
• C、certutil.exe -getkey
• D、certutil.exe -pulse