架空底板总成最小高度是（）

A.基础高度小于250mm时，可做成等厚底板

B.底板纵向分布钢筋，直径6～8mm，间距250～300mm

C.当有垫层时，混凝土的保护层净厚度不宜小于35mm，无垫层时不宜小于70mm

D.基础混凝土的强度等级不宜低于C15

A.0.2m

B.0.3m

C.0.4m

D.0.5m

A.100mm

B.200mm

C.300mm

D.400mm

A.0.1m

B.0.2m

C.0.3m

A.0.5m

B.0.6m

C.0.7m

D.0.8m

A.0~+20mm

B.0~+25mm

C.0~30mm

D.0~35mm

A.0～+25mm

B.0～+35mm

C.0～+50mm

D.0～+70mm

A.0~+25mm

B.0~+35mm

C.0~+50mm

D.0~+80mm

A.0.5

B.0.6

C.0.7

D.0.8

A.0.1

B.0.2

C.0.3

D.0.4