Beakers A, B and C contain Zinc sulphate, silver nitrate and iron (II) sulphate solutions,
respectively. Copper pieces are added to each beaker. The blue colour will appear in case of

Beakers A, B, and C contain zinc sulphate, silver sulphate and iron(II) sulphate solutions respectively. Copper pieces are added to each beaker. The blue colour will appear in case of beaker B.
If we check the order of reactivity series, copper is more reactive than silver and less reactive than zinc and iron. Hence its reaction with copper is
$\mathrm{Cu}+{\mathrm{AgNO}}_3\mathrm{ }\to \mathrm{Cu}{\left({\mathrm{NO}}_3\right)}_2+2\mathrm{Ag}$