What does NPK stand for in the context of fertilisers?

The correct option is Nitrogen, phosphorus, potassium. This answer is correct because it matches the approved learning objective to explain that nitrogen, phosphorus and potassium compounds are used in fertilisers to improve agricultural productivity. (Chemistry only) in the subtopic Production and uses of NPK fertilisers.

The correct option is Nitrogen, phosphorus, potassium. Nitrogen, phosphorus, potassium is correct because it directly supports the approved learning objective to explain that nitrogen, phosphorus and potassium compounds are used in fertilisers to improve agricultural productivity. (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.