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

Consider the following statements:
$(a)$ When the lead-silver alloy is rich in silver,lead is removed by the cupellation process.
$(b)$ Froth flotation can be applied for non-sulphide ores also using a suitable activator.
$(c)$ $PbSO_4 + H_2SO_4$ electrolyte is used for the refining of $Pb$ by electrolysis.
$(d)$ Any metal will not reduce the oxide of other metals which lie above it in the Ellingham diagram.
Using $'T'$ for true and $'F'$ for false statements in the given sequence,select the correct set of code.

In the reaction $4FeCr_2O_4 + 8Na_2CO_3 + 7O_2 \rightarrow X + Y + 8CO_2$,identify $X$ and $Y$.

$A$ metal $(M)$ exists in oxide form. Its oxide cannot be reduced by carbon up to $800\, ^\circ C$,but it can be reduced by $Al$ even below $800\, ^\circ C$. Select the correct Ellingham diagram for metal $(M)$.

Write the uses of alloys.

The electrochemical extraction of aluminum from bauxite ore involves: