The balanced dissociation equation for AlBr3(s) in aqueous solution is AlBr3(s) → Al3+(aq) + 3Br−(aq).
The subject of this question is the dissociation of ionic compounds in aqueous solution, specifically for AlBr3(s). When an ionic compound like AlBr3 dissolves in water, it dissociates into its constituent ions. The correct balanced dissociation equation for AlBr3(s) in aqueous solution is:
AlBr3(s) → Al3+(aq) + 3Br−(aq)
If the compound does not dissociate, you would indicate this with 'NR' which stands for no reaction. Aluminum bromide is an ionic compound, and it does dissociate in water, so NR would not apply in this case.