The most common method of extraction of metals from their oxide ores is :

Metals in the middle of the activity series (such as zinc, iron) are moderately reactive and are usually obtained from their oxides by reduction with carbon. For example, when zinc oxide is heated with carbon, it is reduced to metallic zinc: ${\rm ZnO(s) + C(s) \rightarrow Zn(s) + CO(g)}$. This is distinct from highly reactive metals (obtained by electrolytic reduction) and low-reactivity metals (obtained by heating alone), so option (A) Reduction with carbon is correct.