The Zn is used as a reducing agent in the extraction process of Ag and Au. The reaction is given as, 2[Ag(CN)2](aq)+Zn(s)→2Ag(s)+[Zn(CN)4]2−(aq) The statement ii is also correct as the impure zinc can be refined by the process of distillation.Thus, the option 4 is correct.