Which of the following does not react with oxygen?

Metals that are present above hydrogen in the reactivity series react with oxygen to form basic oxides.

But metals that are present below hydrogen in the reactivity series are less reactive and do not react with oxygen easily. As gold is present below hydrogen in the reactivity series, it will not react with oxygen to form oxide.

So, out of the given metals, Na, Mg, and Zn are present above hydrogen in the reactivity series and easily combine with oxygen to form Na₂O, MgO, and ZnO, respectively. Gold (Ag), being least reactive in nature, does not combine with oxygen. So, it retains the metallic lustre for a longer period and is hence used in jewellery.