Refinements are considered updates for the ____.

george (2¼years ago):
I think it's C, although I'm not sure. As I understand refinements are changes made to the scope without changing the scope, but adding more details to it. WBS is the document about scope. All others are not about scope:

GERT is Graphical Evaluation & Review Technique
ADM is Arrow Diagram Method
CQM is something about quality management, for example Center for Quality Management

None of them are about scope.