Which of the following ligand-exchange reactions is strongly favoured according to HSAB theory?
[Ag(H₂O)₂]⁺ + 2 I⁻ → [AgI₂]⁻ + 2 H₂O
[AlF₆]³⁻ + 6 NH₃ → [Al(NH₃)₆]³⁺ + 6 F⁻
[Fe(H₂O)₆]³⁺ + 6 CN⁻ → [Fe(CN)₆]³⁻ + 6 H₂O
[Mg(H₂O)₆]²⁺ + 6 I⁻ → [MgI₆]²⁻ + 6 H₂O