单项选择题

A.涂抹水泥砂浆每遍适宜厚度为5~7mm
B.涂抹水泥混合砂浆每遍适宜厚度为7~9mm
C.纸筋石灰面层赶平压实厚度不得大于4mm
D.石膏灰面赶平压实厚的厚度不得大于2mm