Which of the following factors is of no significance for roasting sulfide oxe to the oxides and not subjecting the sulfide are to carbon reduction directly ?

Question

$\begin{array}{1 1} \text{Metal sulphide are less stable than the corresponding oxides} \\ \text{$CO_2$ more volatile than $CS_2$ } \\ \text{Metal sulphide are thermo dynamically more stable than $CS_2$ } \\ \text{$CO_2$ is thermodynamically more than $CS_2$ } \end{array} $