从油层的地质条件出发，将水质指标按地层的（）分为3类。

A.-0.1～0.1mg/L
B.0～0.1mg/L
C.0.1～0.2mg/L
D.0.1～0.5mg/L

A.≤1.0mg/L
B.≤2.0mg/L
C.≤3.0mg/L
D.≤0.5mg/L

A.10个/ml
B.100个/ml
C.1000个/ml
D.10000个/ml