Among the following cations, the number of cations which will give characteristic precipitate in their identification tests with \(K_4\)[{Fe(CN)}\(_6\)] is :
\[
{Cu}^{2+}, \, {Fe}^{3+}, \, {Ba}^{2+}, \, {Ca}^{2+}, \, {NH}_4^+, \, {Mg}^{2+}, \, {Zn}^{2+}
\]