Which of the following is not a possible cause of an unfavorable direct labor efficiency variance？下列哪项不是造成不利的直接劳动效率差异的可能原因？

A.Lack of motivation. 缺乏激励

B.Low-quality materials.劣质材料

C.Poor supervision.监督不力

D.All of the selections could be considered possible causes of an unfavorable labor efficiency variance.所有的选项都可以被认为是不利的劳动效率差异的可能原因。

正确答案：All of the selections could be considered possible causes of an unfavorable labor efficiency variance.所有的选项都可以被认为是不利的劳动效率差异的可能原因。