Which of the following processes is $NOT$ involved in the extraction of metal from cassiterite $(SnO_2)$ ore?

$A$ piece of steel is heated until redness and then plunged into cold water or oil. This treatment of iron makes it:

Which of the following alloys contains $Ni$ metal?

The reaction that does $NOT$ take place in a blast furnace between $900 \ K$ to $1500 \ K$ temperature range during the extraction of iron is:

The important advantage$(s)$ of Lintz and Donawitz $(L.D.)$ process for the manufacture of steel is (are):

The correct statement$(s)$ related to the metal extraction processes is(are):
$(A)$ $A$ mixture of $PbS$ and $PbO$ undergoes self-reduction to produce $Pb$ and $SO_2$.
$(B)$ In the extraction process of copper from copper pyrites,silica is added to produce copper silicate.
$(C)$ Partial oxidation of sulphide ore of copper by roasting,followed by self-reduction produces blister copper.
$(D)$ In the cyanide process,zinc powder is utilized to precipitate gold from $Na[Au(CN)_2]$.