How many of the following metals is extracted by self reduction process?

$\mathrm{Pb}, \mathrm{Au}, \mathrm{Mg}, \mathrm{Sn}, \mathrm{Fe}, \mathrm{Al}, \mathrm{Ag}, \mathrm{Hg}, \mathrm{Na}, \mathrm{Zn}, \mathrm{Cu}, \mathrm{Ca}$

Commercial self-reduction extraction of copper, lead, and mercury is done from the appropriate ores.
Due to their lower electropositivity, copper, lead, and mercury can all be obtained through self-reduction from their respective sulphide ores.

$\mathrm{Pb},\mathrm{Cu},\mathrm{Hg}$