Among the following cations, the number of cations which will give characteristic precipitate in their identification tests withK4K_4K4[Fe(CN)6_66] is : Cu2+, Fe3+, Ba2+, Ca2+, NH4+, Mg2+, Zn2+ {Cu}^{2+}, \, {Fe}^{3+}, \, {Ba}^{2+}, \, {Ca}^{2+}, \, {NH}_4^+, \, {Mg}^{2+}, \, {Zn}^{2+} Cu2+,Fe3+,Ba2+,Ca2+,NH4+,Mg2+,Zn2+