Fixed costs OA) are fixed on a per-unit basis, but vary in total OB) are fixed on a per-unit basis, and fixed in total OC) vary on a per-unit basis, and vary in total D) vary on a per-unit basis, but are fixed in total use(s) the output of an activity-based costing system to improve the operational control of an organization. A) Cost-volume-profit models B) Traditional costing system C) Activity-based management D) Cost accounting