The following reaction is named as:

\(\mathrm{Ar} \mathrm{N}_2^{+} \mathrm{Cl}^{-} \xrightarrow{\mathrm{Cu}/ \mathrm{HCl}} \mathrm{ArCl}+\mathrm{N}_2+\mathrm{CuCl}\)
1. Sandmeyer reaction
2. Gattermann reaction
3. Claisen reaction
4. Carbylamine reaction