Explanation

(a)
The process of extraction of metal by heating roasted ore with coke in the presence of a flux is called smelting. It is done in blast furnace. Iron is extracted by this process.
${Fe}_{2}O_{3} + 3C\ \overset{> 1123\ K}{\rightarrow}2Fe + 3CO$
${Fe}_{2}O_{3} + 3CO\ \overset{1123\ K}{\rightarrow}2Fe + 3{CO}_{2}$