Question

(a) Baryte,
(b) Galena,
(c) Zinc blende and
(d) Copper pyrites.
How many of these minerals are sulphide based?

Answer 1

Baryte: $BaSO_4$
Galena: $PbS$
Zinc blende: $ZnS$
Copper pyrites: $CuFeS_2$
Only three are sulphide based.

So, the answer is $3$.