To form product [C] multiple name reactions are taking place.

To form product [A] when aromatic amine react with nitrous acid it forms diazonium salt which when treated with copper salts as reagent forms aryl halides and reaction is called as Sendmeyer reaction.

Now product [A] that is when treated with ${\mathrm{Cl}}_2$ in presence of sunlight, free radical substitution takes place and [B] is formed.

Now when [B] is treated with sodium metal in presence of dry ether forms product [B] by Wurtz reaction.

Overall reaction takes place as: