The formulae for some ions are given below. In which row is the formula incorrect?
- Aaluminium sulfate, $\text{Al}_2(\text{SO}_4)_3$
- Bcalcium nitrate, $\text{Ca}(\text{NO}_3)_2$
- Ciron(III) bromide, $\text{Fe}_3\text{Br}$
- Dpotassium sulfide, $\text{K}_2\text{S}$