Assertion :The metal sulphides and carbonates are converted to metal oxides in the process of extraction of metal from them.
Reason :Easier to obtain metal from its oxide, as compared from its sulphides and carbonates.

All the metal sulphides and carbonates are converted to their respective metal oxides as it is easier to extract the metals from their respective oxides. This owes to the difference in Gibbs free energy in the reaction of obtaining metal from its sulphides/carbonates and oxides. The reaction of obtaining metals from oxides has a more negative $\Delta G$ value than that of the reaction of obtaining metals from their sulphides/carbonates.