单项选择题
A.≤0.07B.≤0.05C.≤0.03D.≤0.01
A.≤0.60B.≤0.40C.≤0.20D.≤0.10
A.≤0.1/1000B.≤0.2/1000C.≤0.5/1000D.≤0.8/1000