Provide one caveat that will affect whether a production-volume variance is a good measure of the economic cost of unused capacity. A. The production-volume variance takes into account all information needed to be a good measure of the economic cost of unused capacity except in cases where there is excess plant capacity. B. A favorable production-volume variance is not always desirable. C. What change in selling price might have been necessary to attain the level of sales assumed in the denominator of the fixed manufacturing overhead rate. D. An unfavorable production-volume variance only measures the over-allocation of fixed overhead cost caused by production levels higher than those at capacity