The reaction $Na^{+}Cl^{-} \quad \underrightarrow{Cu/HCl} \quad Arcl+N_2+CuCl$ is named as

Question

$\begin{array}{1 1} \text{sand meyer reaction } \\ \text{Gattermun reaction } \\ \text{Claisen reaction } \\ \text{Carbylamine reaction } \end{array} $