The equation which is balanced and represents the correct product(s) is:
(a) Li2O +2KCl→2LiCl+K2O
(b) [CoCl(NH3)5]++5H+→Co2++5NH4++Cl-
(c) [Mg(H2O)6]2+ +(EDTA)4-→Excess NaOH[Mg(EDTA)]2++6H2O
(d) CuSO4+4KCN→K2[Cu(CN)4+K2SO4