Detailed Explanation:

Smelting is the metallurgical process where ore is heated with a reducing agent (like coke) to extract the metal in a fused (molten) state, separated from slag.

Roasting converts sulfides to oxides in excess air, calcination removes volatile impurities in limited air, and froth flotation is a physical concentration method—none produce molten metal directly.

Therefore, only smelting yields metal in a fused state, making Option 4 the correct answer.