Leaching of gold with dilute aqueous solution of \( \mathrm{NaCN} \) in presence of oxygen gives complex [A], which on reaction with zinc forms the elemental gold and another complex [B]. [A] and [B], respectively are:
Sum of oxidation state (magnitude) and coordination number of cobalt in \( \text{Na[Co(bpy)Cl}_4] \) _______.
