Main source of lead is PbS. It is converted to Pb by :

Self-reduction process is :

$\mathrm{Pbs}$ converts $\mathrm{Pbo}$ into Pb, releasing $S{O}_2$. This practice is known as self-reduction.

$\mathrm{PbS}\underset{\mathrm{\Delta }}{\stackrel{\text{ air }}{⟶}}\mathrm{PbO}+{\mathrm{SO}}_2$

$\mathrm{PbS}\to \mathrm{Pb}+{\mathrm{SO}}_2$

Hence, option B is correct.