Match List-$I$ with List-$II$ and select the correct code.

List-$I$	List-$II$
$I.$ Cyanide process	$a.$ Ultrapure $Ge$
$II.$ Froth floatation process	$b.$ Pine oil
$III.$ Electrolytic reduction	$c.$ Extraction of $Al$
$IV.$ Zone refining	$d.$ Extraction of $Au$

The form of iron having the highest carbon content is

Among the following compounds,the number of those present in copper matte is $......$
$A.$ $CuCO_3$
$B.$ $Cu_2S$
$C.$ $Cu_2O$
$D.$ $FeO$

The electrochemical extraction of aluminum from bauxite ore involves:

In aluminium extraction by the Bayer process, alumina is extracted from bauxite by sodium hydroxide at high temperature and pressure: $Al_2O_{3(s)} + 2 OH^-_{(aq)} + 3 H_2O_{(l)} \rightarrow 2 [Al(OH)_4]^-_{(aq)}$. Solid impurities such as $Fe_2O_3$ and $SiO_2$ are removed and then $[Al(OH)_4]^-$ is reprecipitated: $2 [Al(OH)_4]^-_{(aq)} \rightarrow Al_2O_3 \cdot 3 H_2O_{(s)} + 2 OH^-_{(aq)}$. In the industrial world:

In which of the following metals extraction,impurities are removed as slag?
$i.$ $Al$ $\quad$ $ii.$ $Fe$
$iii.$ $Cu$ $\quad$ $iv.$ $Zn$
The correct option is