The correct option is
The chemical formulae of zinc blende is ZnS.
1. The first step in metallurgy is mining the ore out of earth's crust.
2. After crushing and pulverising, a sulphide ore is concentrated by froth flotation.
3. This ore is then reduced to its oxide by roasting it in excess supply of air.
ZnS(s) + O2(g) Δ→ ZnO(s) + SO2(g)
4. This oxide obtained is further reduced with carbon to obtain crude metal, which is refined to obtain pure metal.
ZnO(s) + C(s) → Zn(s) + CO2(g)