单项选择题

A.YouplantoinstallanEnterprisecertificationauthority(CA)onadedicatedstand-aloneserver.WhenyouattempttoaddtheActiveDirectoryCertificateServices(ADCS)role,youfindthattheEnterpriseCAoptionisnotavailable.YouneedtoinstalltheADCSroleasanEnterpriseCA.Whatshouldyoudofirst()
A.AddtheDNSServerrole.
B.Jointheservertothedomain.
C.AddtheWebserver(IIS)roleandtheADCSrole.
D.AddtheActiveDirectoryLightweightDirectoryService(ADLDS)role.