二次精盐水质量Ca²⁺+Mg²⁺≤（）

A.30±5kPa
B.35±5kPa
C.36±5kPa
D.40±5kPa

A.180~190g/l
B.190~220g/l
C.190~200g/l
D.200~220g/l

A.3%
B.4%
C.5%
D.6%