Which of the following statements about the advantage of roasting of sulphide ore before reduction is not true? 

• A

  ${\mathrm{\Delta }}_f{G}^{\mathrm{\Theta }}$ of the sulphide is greater than  ${\mathrm{CS}}_2$ and ${\mathrm{H}}_2\mathrm{S}$

• B

  ${\mathrm{\Delta }}_f{G}^{\mathrm{\Theta }}$ is negative for roasting of sulphide ore to oxide 

• C

  Roasting of the sulphide to oxide is thermodynamically feasible 

• D

  Carbon and hydrogen are suitable reducing agents for metal sulphides