You have a Windows Server 2008 R2 that has the Active Directory Certificate Services server  role installed.   You need to minimize the amount of time it takes for client computers to download a certificate  revocation list （CRL）.     What should you do（）

A.Install and configure an Online Responder.

B.Install and configure an additional domain controller.

C.Import the Root CA certificate into the Trusted Root Certification Authorities store on all client workstations.

D.Import the Issuing CA certificate into the Trusted Root Certification Authorities store on all client workstations.