Which of the following sulphides do not dissolve in 50% ${\mathrm{HNO}}_3$ but dissolve in aqua regia?

As the solubility constant of mercury sulphide is very low. Hg and sulphide cooperate as a solid Hg-sulfide complex at very low concentrations, there are no water-soluble mercury compounds, particularly sulphide, at pH levels over 8. Thus, hgs sulphides dissolve in 50% ${\mathrm{HNO}}_3$.

Hence correct options are a, b, d