单项选择题

A.1:2水泥砂浆,砂浆厚度6~10mm
B.1:3水泥砂浆,砂浆厚度6~8mm
C.1:1:6混合砂浆,砂浆厚度15mm
D.1:2水泥砂浆,砂浆厚度10~15mm