木楼梯（ 010503003 ）项目适用于楼梯和爬梯，工程量按设计图示尺寸以水平投影面积计算，不扣除宽度小于（      ）的楼梯井，伸入墙内部分不计算。（ 179 页）

A、<span style="FONT-FAMILY: " lang="EN-US">200mm</span><span style="FONT-FAMILY: " lang="EN-US"></span>

B、<span style="FONT-FAMILY: " lang="EN-US">300mm</span>

C、<span style="FONT-FAMILY: " lang="EN-US"><span style="mso-spacerun: yes"></span> <chmetcnv unitname="mm" sourcevalue="400" hasspace="False" negative="False" numbertype="1" tcsc="0" w:st="on" />400mm </span>

D、<span style="FONT-FAMILY: " lang="EN-US">500mm</span>