A.≥0.5米 B.≥0.4米 C.≥0.3米 D.≥0.2米
A.0.6~0.9 B.0.5~0.7 C.0.4~0.6 D.0.5~0.6
A.0.9~1.0 B.1.0~1.2 C.0.9~1.1 D.0.9~1.2