单项选择题
A.≥98% B.≥98.5% C.≥99.0%
A.≤0.1% B.≤0.15% C.≤0.2%
A.7μg/l;0.007μg/l B.8mg/l;0.007μg/l C.8mg/l;0.007mg/l D.7μg/l;0.007mg/l