An inorganic Compound \('\mathrm{X}^{\prime}\) on treatment with concentrated \(\mathrm{H}_{2} \mathrm{SO}_{4}\) produces brown fumes and gives dark brown ring with \(\mathrm{FeSO}_{4}\) in presence of concentrated \(\mathrm{H}_{2} \mathrm{SO}_{4} .\) Also Compound \('\mathrm{X}'\) gives precipitate \('Y',\) when its solution in dilute \(\mathrm{HCI}\) is treated with \(\mathrm{H}_{2} \mathrm{~S}\) gas. The precipitate \('Y'\) on treatment with concentrated \(\mathrm{HNO}_{3}\) followed by excess of \(\mathrm{NH}_{4} \mathrm{OH}\) further gives deep blue coloured solution, Compound \('X'\) is :

1. A \(\mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}\)
2. B \(\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}\)
3. C \(\mathrm{Pb}\left(\mathrm{NO}_{2}\right)_{2}\)
4. D \(\mathrm{Co}\left(\mathrm{NO}_{3}\right)_{2}\)