After partial roasting,the sulphide of copper is reduced by

Consider the following reactions of metallurgy:
Ore '$X$' $\xrightarrow{\text{Roasting}}$ '$Y$' + $SO_2$ $\uparrow$
Ore '$Z$' $\xrightarrow{\text{Calcination}}$ '$Y$' + $CO_2$ $\uparrow$
'$Y$' + $C$ $\xrightarrow{1673 \ K}$ '$A$' (vapour) + '$B$' $(g)$
where '$A$' and '$B$' are respectively:

The Ellingham diagram of a certain metal $M$ is represented in the figure. The points $A$ and $B$ respectively correspond to:

Copper matte is obtained after which of the following processes?

In the extraction of silver,$Ag_2S$ is dissolved in :

During the extraction of silver,which of the following is formed?