Which alloy contains $Cu$,$Sn$,and $Zn$?

The process of the extraction of copper from copper pyrites involves:-
$(I)$ Froth floatation $(II)$ Calcination $(III)$ Roasting $(IV)$ Self reduction $(V)$ Smelting $(VI)$ Liquation $(VII)$ Electrorefining

Which of the following statement$(s)$ is/are incorrect?

Select the correct option regarding the processes used during metal extraction from their ores.

Flux is used to remove..........

Which among the following statement$(s)$ is(are) true for the extraction of aluminium from bauxite?
$A$. Hydrated $Al_2O_3$ precipitates,when $CO_2$ is bubbled through a solution of sodium aluminate.
$B$. Addition of $Na_3AlF_6$ lowers the melting point of alumina.
$C$. $CO_2$ is evolved at the anode during electrolysis.
$D$. The cathode is a steel vessel with a lining of carbon.