单项选择题
A.75mm龙骨+12mm耐火石膏板内填防火岩棉隔墙 B.双面抹灰的100mm厚轻砌块隔墙 C.100mm龙骨+12石膏板内填防火岩棉隔墙
A.1/2 B.1/3 C.1/4 D.1/5
A.1 B.2 C.3 D.4