阳台、楼板、屋面的防护栏杆应由上、下两道横杆及栏杆柱组成,上杆离地高度为( ),下杆离地高度为( )。
A:1.0~1.2m,0.5~0.6m
B:1.5~1.8m,0.6~0.8m
C:1.2~1.5m,0.7~0.9m
D:1.0~1.5m,0.4~0.5m
出自:安全员