What should you perform?

You have a server named Data1 that runs a Server Core Installation of Windows Server 2012 R2 Standard.
You need to configure Data1 to run a Server Core Installation of Windows Server 2012 R2 Datacenter. You
want to achieve this goal by using the minimum amount of administrative effort.
What should you perform?

A.
An online servicing by using Dism

B.
An offline servicing by using Dism

C.
An upgrade installation of Windows Server 2012 R2

D.
A clean installation of Windows Server 2012 R2

Explanation:
There are a couple of ways to install the GUI from the command prompt, although both use the same toolDISM (Deployment Image Service Manager). When you are doing it for a single (local) server, the command is:
DISM.exe /Online {/Get-CurrentEdition | /Get-TargetEditions | /Set-ProductKey:<product_key> | /SetEdition:<target_edition> {/GetEula:< path> | /AcceptEula/ProductKey:<product_key>}}
Dism /online /enable-feature /featurename:ServerCore-FullServer /featurename:…