Formation of metallic copper from the sulphide ore in the normal thermo-metallurgical process essentially involves which one of the following reactions?

• A
  $CuS + \frac{3}{2} O_2$ $\rightarrow CuO + SO_2; \ CuO + C$ $\rightarrow Cu + CO$
• B
  $CuS + \frac{3}{2} O_2$ $\rightarrow CuO + SO_2; \ 2CuO + CuS$ $\rightarrow 3Cu + SO_2$
• C
  $CuS + 2O_2$ $\rightarrow CuSO_4; \ CuSO_4 + CuS$ $\rightarrow 2Cu + 2SO_2$
• D
  $CuS + 2O_2$ $\rightarrow CuO + SO_2; \ CuO + CO$ $\rightarrow Cu + CO_2$