A primary amine 'A' $\displaystyle \mathrm{C}_{2} \mathrm{H}_{7} \mathrm{~N}$ reacts with alkyl halide $\displaystyle \left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{I}\right)$ to give secondary amine 'B'. 'B' reacts with $\displaystyle \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{SO}_{2} \mathrm{Cl}$ to give a solid 'C' which is insoluble in alkali. Identify 'A', 'B', 'C' and write all the chemical reactions involved.

\(\displaystyle \mathrm{A}=\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{NH}_{2} /\) Ethanamine,\(\displaystyle \mathrm{B}=\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH} / \mathrm{N}\)-Ethyl ethanamine, \(\displaystyle \mathrm{C}=\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{SO}_{2} \mathrm{~N}\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} / \mathrm{N}, \mathrm{N}\)-Diethylbenzenesulphonamide \(\displaystyle \mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{NH}_{2} \xrightarrow{\mathrm{C}_{2}\mathrm{H}_{5}\mathrm{I}} \left(\mathrm{C}_{2}\mathrm{H}_{5}\right)_{2}\mathrm{NH}\) \(\displaystyle \left(\mathrm{C}_{2}\mathrm{H}_{5}\right)_{2}\mathrm{NH} \xrightarrow{\mathrm{C}_{6}\mathrm{H}_{5}\mathrm{SO}_{2}\mathrm{Cl}} \mathrm{C}_{6}\mathrm{H}_{5}\mathrm{SO}_{2}\mathrm{N}\left(\mathrm{C}_{2}\mathrm{H}_{5}\right)_{2}\)