下述哪一项病理改变可见于白色皱襞性龈口炎（）

A.角化过度

B.粒层明显

C.棘层松解和上皮内疱

D.上皮显著增厚，棘细胞肿胀，淡染

E.结缔组织大量淋巴细胞浸润

Which of the following most accurately describes the shapes of the average variable cost (AVC) and average total cost (ATC) curves（）

A. The AVC and ATC curves are both U-shaped.

B. The AVC and ATC curves both decrease initially, and then flatten.

C. The AVC curve is U-shaped whereas the ATC curve declines initially then flattens.