Identification of ions and gases — practice question

Which ion gives a precipitate that dissolves in excess with both aqueous ammonia and aqueous sodium hydroxide?

• Acalcium ion, $\text{Ca}^{2+}$
• Bcopper(II) ion, $\text{Cu}^{2+}$
• Ciron(III) ion, $\text{Fe}^{3+}$
• Dzinc ion, $\text{Zn}^{2+}$