An activity-based costing system that is designed for internal decision-making will not conform to generally accepted accounting principles because: A) some manufacturing costs (i.e., the costs of idle capacity and organization-sustaining costs) will not be assigned to products. B) some non-manufacturing costs are assigned to products. C) first-stage allocations may be based on subjective interview data. D) all of the above are reasons why an activity-based costing system that is designed for internal decision-making will not conform to generally accepted accounting principles