What are the steps involved in purifying copper? (In order of precedence)

• A. Smelting-Roasting-Converting
• B. Smelting-Converting-Roasting
• C. Converting-Roasting-Smelting
• D. Roasting-Smelting-Converting
• E. Smelting-Roasting-Convertingb) Smelting-Converting-Roastingc) Converting-Roasting-Smeltingd) Roasting-Smelting-Converting