Metal above in activity series are more reactive and can displace the less reactive metal.
(i) $\mathrm{NaCl}$ solution and copper metal
$\mathrm{Na}$ is more reactive than $\mathrm{Cu}$, thus it will not give displacement reaction.
(ii) ${\mathrm{AgNO}}_3$ solution and copper metal.
$\mathrm{Ag}$ can be replaced by $\mathrm{Cu}$ as it is above silver in the reactivity series. Therefore, this pair will give displacement reaction.
(iii) ${\mathrm{Al}}_2{\left({\mathrm{SO}}_4\right)}_3$ solution and magnesium metal. Magnesium is more reactive than aluminium hence displacement reaction will occur and Magnesium sulphate is formed.
(iv) ${\mathrm{ZnSO}}_4$ solution and iron metal
The displacement reaction does not occur because iron metal is less reactive than zinc metal. So, a less reactive iron metal cannot displace a more reactive zinc metal from zinc sulphate solution.