The correct option is C Self-reduction step to produce 'blister copper' following evolution of SO2
First, the ore is ground into a fine powder through crushing and grinding. Since the ore is a sulphide ore, it is concentrated using froth-floatation.
Eventually, the iron in CuFeS2 is removed as FeSiO3 - as slag.
The mixture of Cu2S and Cu2O undergoes self-reduction to yield blister copper (there are blisters because of the evolution of SO2 and other gases).
It is then refined electrolytically to get very pure metallic copper.