Which of the following fertilizers include potassium as a component?

Explanation

Both Sulfate of Potash (SOP) and Muriate of Potash (MOP) are common potassium-containing fertilizers. Although Chilean saltpeter (Chilean Nitrate) is primarily known for nitrogen, it may also contain potassium in some formulations. Therefore, all listed options include potassium, making 'All of these' the correct choice.