The correct statement(s) regarding the binary transition metal carbonyl compounds is(are) (Atomic numbers : $$Fe = 26,Ni = 28$$)

Addition of excess aqueous ammonia to a pink colored aqueous solution of $$MC{l_2},6{H_2}O\left( X \right)$$ and $$N{H_4}Cl$$ gives an octahedral complex $$Y$$ in the presence of air. In aqueous solution, complex $$Y$$ behaves as $$1:3$$ electrolyte. The reaction of $$X$$ with excess $$HCl$$ at room temperature results in the formation of a blue colored complex $$Z.$$ The calculated spin only magnetic moment of $$X$$ and $$Z$$ is $$3.87$$ $$B.M.,$$ whereas it is zero for complex $$Y.$$ Among the following options, which statement(s) is (are) correct?