Which of the following is NOT a method of extracting copper from its compounds?

The correct option is Fermentation. This answer is correct because it matches the approved learning objective to describe how copper can be obtained from solutions of copper compounds by electrolysis. (HT only) in the subtopic Alternative methods of extracting metals.

The correct option is Fermentation. Fermentation is correct because it directly supports the approved learning objective to describe how copper can be obtained from solutions of copper compounds by electrolysis. (HT only). This belongs to the subtopic Alternative methods of extracting metals within Using the Earth's resources and obtaining potable water, so the explanation must stay tied to that curriculum context. The other options are incorrect because they either do not answer this learning objective, use a vague statement, or move away from Alternative methods of extracting metals.