An aromatic compound $\left(\mathrm{A}\right)$ on heating with ${\mathrm{NH}}_3$ and ${\mathrm{Cu}}_2\mathrm{O}$ at high pressure gives $\left(\mathrm{B}\right)$. The compound $\left(\mathrm{B}\right)$ on treatment with ice cold solution of ${\mathrm{NaNO}}_2$ and $\mathrm{HCl}$ gives $\left(\mathrm{C}\right)$, which on heating with $\mathrm{Cu}/\mathrm{HCl}$ gives compound $\left(\mathrm{A}\right)$ again. Identify the compounds $\left(\mathrm{A}\right), \left(\mathrm{B}\right)$ and $\left(\mathrm{C}\right)$. Write the name of the reaction for the conversion of $\left(\mathrm{B}\right)$ to $\left(\mathrm{C}\right)$.