Answer: C
Assertion (A) is true — sulphide ores must be roasted (converted to oxides) before reduction to extract the metal. Reason (R) is false — roasting converts sulphide ores into metal oxides, not directly into metals.
The key distinction: roasting ($2\text{ZnS} + 3\text{O}_2 \rightarrow 2\text{ZnO} + 2\text{SO}_2$) produces a metal oxide, which is then reduced (e.g., by carbon) to get the metal. Examiners expect you to know the two-step process. The Reason wrongly claims roasting gives the metal directly — making R false while A remains correct.