单项选择题

A.砌完墙后用1:1水泥砂浆或加色砂浆勾缝
B.砌完墙后用1:1.5水泥砂浆或加色砂浆勾缝
C.砌完墙后用1:2水泥砂浆或加色砂浆勾缝
D.砌完墙后用1:2.5水泥砂浆或加色砂浆勾缝