Which of the following steps should be taken to back up an individual registry key?

Which of the following steps should be taken to back up an individual registry key?

A.
Open the registry editor, select the key to export, select File/Export, select Save.

B.
Rename the registry file to *.bak.

C.
Open the registry editor, select File/Import, select Save.

D.
Copy the registry file to another location.