Hard water does not contain `:-`

Options

A. `Ca^(2+)` with `HCO_(3)^(-)`
B. `Mg^(2+)` with `SO_(4)^(2-)`
C. `Mg^(2+)` with `Cl^(-)`
D. `Ca^(2+)` with `CO_(3)^(2-)`

Answer

D

Explanation

`N//A`