Which of the following statements about NPK fertilisers is true?

The correct option is They are made from nitrogen, phosphorus, and potassium compounds. This answer is correct because it matches the approved learning objective to define NPK fertilisers as fertilisers containing compounds of nitrogen, phosphorus and potassium. (Chemistry only) in the subtopic Production and uses of NPK fertilisers.

The correct option is They are made from nitrogen, phosphorus, and potassium compounds. They are made from nitrogen, phosphorus, and potassium compounds is correct because it directly supports the approved learning objective to define NPK fertilisers as fertilisers containing compounds of nitrogen, phosphorus and potassium. (Chemistry only). This belongs to the subtopic Production and uses of NPK fertilisers within The Haber process and the use of NPK fertilisers, 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 Production and uses of NPK fertilisers.