Cost of quality is the total cost of all efforts to achieve product/service quality, and includes all work to ensure conformance to requirements. All of the following are costs that are incurred EXCEPT （）.

A．cost of poor quality

B．opportunity cost

C．external failure cost

D．appraisal cost

下列普通纸面石膏板隔墙上乳胶漆墙面的工程做法，从外向内表述，其中哪条做法是错误的[2003-090]（）

A.喷合成树脂乳液涂料饰面

B.封底漆一道

C.满刮2mm厚耐水腻子分遍找平

D.刷界面剂一道