ANS:B - copper

The fire refining process is commonly employed in the purification of copper. In the fire refining process, impure copper is melted in a furnace and subjected to a controlled oxidation-reduction reaction. During this process, impurities such as sulfur, oxygen, and other metallic impurities are oxidized and removed as slag or gas. The remaining molten copper is then cast into desired shapes such as ingots or bars. Fire refining is particularly effective for removing impurities that have a higher affinity for oxygen compared to copper, allowing for the production of high-purity copper suitable for various industrial applications, including electrical wiring, electronics, and plumbing.