You need to start using key archival

You are the network administrator for your organization. Your company uses a Windows Server 2012 Enterprise certification authority to issue certificates. You
need to start using key archival.
What should you do?

A.
Implement a distribution CRL.

B.
Install the smart card key retrieval.

C.
Implement a Group Policy object (GPO) that enables the Online Certificate Status Protocol (OCSP) responder.

D.
Archive the private key on the server.