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

• A、Install and configure an Online Responder.
• B、Install and configure an addtional domain controller.
• C、Import the Root CA certificate into the Trusted Root Certification Authorities on all client workstations.
• D、Import the Issuing CA certificate into the Trusted Root Certification Authorities on all client workstations.