A white crystalline substance dissolves in water. On passing $H_2S$ in this solution, a black ppt. is obtained. The black ppt. dissolves completely in hot $HNO_3$. On adding a few drops of conc. $H_2SO_4$, a white ppt. is obtained. The ppt. is that of

Question

(a) $BaSO_4$
(b) $SrSO_4$
(c) $PbSO_4$
(d) $CdSO_4$