Your network contains an enterprise root certification authority （CA）.  You need to ensure that a certificate issued by the CA is valid.  What should you do（）

• A、Run syskey.exe and use the Update option. T.he safer ，easier way to help you pass any IT exams.  4 / 90
• B、Run sigverif.exe and use the Advanced option.  
• C、Run certutil.exe and specify the -verify parameter.  
• D、Run certreq.exe and specify the -retrieve parameter.