In roasting:

In roasting moisture is removed, non-metal as their volatile oxide are removed and ore becomes porous.

Roasting is the process of heating a material below its melting point while it is exposed to an abundance of air or oxygen. In metallurgical operations, when ores are transformed into oxides and subsequently metals are recovered, roasting is utilized. Sulfide ores are often converted using it.

Hence, option D is correct.