单项选择题
A.>0.25% B.>0.35% C.>0.45% D.>0.6%
A.≤0.25% B.≤0.15% C.0.25%—0.6% D.>0.6%
A.≤0.35% B.≤0.25% C.≤0.45% D.>0.6%