To determine which compound is most stable, we need to consider the factors that contribute to the stability of coordination compounds.$\newline$Stability of coordination compounds is influenced by:$\newline$• The nature of the ligands: Strong field ligands form more stable complexes.$\newline$• The oxidation state of the metal: Higher oxidation states generally lead to more stable complexes.$\newline$• The chelate effect: Chelating ligands form more stable complexes compared to monodentate ligands.$\newline$Let's analyze each option:$\newline$