Sometimes it’s important to remove an RODC from your forest or domain.
However, it’s important that you follow a simple rule whilst removing RODC’s.
What is this rule?
A.
All RODC’s must be detached before removing a final writable domain controller
B.
All writable domain controllers must be removed before RODC’s can be detached
C.
Your forest must only consist of RODC’s if you want to remove them
D.
There are no rules for removing RODC’s
Explanation:
After researching this and using logic, we need a writable DC for a RODC to exist, therefore we have to remove
all RODC’s before removing the last writable DC.
Can you remove the last domain controller in a domain if there are unoccupied (or disabled) RODC accounts in the domain?
As for all previous versions of Windows Server, it is a requirement that all other domain controllers have been removed from the domain before you can remove the last domain controller. For Windows Server 2008, this requirement includes the removal of all RODCs and the removal of any precreated but unused RODC accounts
https://technet.microsoft.com/en-us/library/cc754956(v=ws.10).aspx
Question ask the rule to remove a rodc not a writable domain controller.
In that case Answer A would be correct.
But I think correct answer is D. There’s no rule for removing a rodc.