单项选择题

A.0.5-3.0mg/L,0.05-3.0mg/L
B.0.5-2.0mg/L,0.05-2.0mg/L
C.0.5-2.0mg/L,0.02-3.0mg/L
D.0.5-3.0mg/L,0.02-2.0mg/L