Among PbS, CuS, HgS, MnS, Ag_(2)S,NiS,CoS,Bi_(2)S_(3), and SnS_(2) the total number of BLACK coloured sulphides is:

Among PbS, CuS, HgS, MnS, Ag_(2)S,NiS,CoS,Bi_(2)S_(3), and SnS_(2) the

1.	Among PbS, CuS, HgS, MnS, Ag_(2)S,NiS,CoS,Bi_(2)S_(3), and SnS_(2) the total number of BLACK coloured sulphides is:
Answer» ANSWER :7