A company has an Active Directory forest.
You plan to installan offline Enterprise root certification authority (CA)on a servernamed CA1.
CA1is a memberof the PerimeterNetwork workgroupand is attached to a hardware security module for
private key storage.
You attempt to add the Active Directory Certificate Services (AD CS) server role to CA1.
The Enterprise CA option is not available.
You needto install the AD CS server role as an Enterprise CA on CA1.
What should you do first?

A.
Add the DNS Server server role to CA1.

B.
Add the Web Server (IIS) server role and the AD CS server role to CA1.

C.
Add the Active Directory Lightweight Directory Services (AD LDS) server role to CA1.

D.
Join CA1 to the domain.

Explanation:
Reference 1:
http://kazmierczak.eu/itblog/2012/09/23/enterprise-ca-option-is-greyed-out-unavailable/
Many times, administrators ask me what to do when installing Active Directory Certificate Services they cannot
choose to install Enterprise Certification Authority, because it’s unavailable.
Well, you need to fulfill basic requirements:
1. Server machine has to be a member server (domain joined).
2. (…)
Reference 2:
http://social.technet.microsoft.com/Forums/en/w7itproSP/thread/34f95b81-b196-4211-9a99-a06108521268
I am trying to install a new enterprise root CA on my windows server 2008 r2 system, but the enterprise option
is always greyed out. The server was originally setup and put on the domain, but has since been removed from
the domain and left in a workgroup.
its greyed out because it’s not in a domain; that’sone of the requirements for Enterprise CA.