Correct Answer: A
Configuration Management is a broad discipline used to track and manage changes to, well, everything. In the context of Project Management, it is used to track and manage any changes to the official documents of the project, including requirements. The PMBOK specifically defines the CCB, the Change Control Board, as being a group of stakeholders with responsibility for approving changes to the Project Baseline. This is more specific than "all acceptance decisions". Changes, which are not changes to the baseline, can be tracked through CM, without requiring approval by the CCB. However, to split hairs, there is certain confusion in saying that Configuration Management describes the physical characteristics of the product of the project. Requirements documents describe those characteristics, CM is used to control changes to those requirements.