Which of the following are macronutrients commonly found in soil?

Concept: In agronomy, mineral plant nutrients drawn from the soil solution are classified by how much of them a crop needs: primary macronutrients (nitrogen, phosphorus, potassium) are required in the largest amounts and are the ones most often deficient in cultivated soils; secondary macronutrients (calcium, magnesium, sulfur) are needed in moderate amounts; and micronutrients (iron, manganese, zinc, boron, copper, molybdenum, and a few others) are needed only in trace amounts. Carbon, hydrogen, and oxygen are also essential to plant growth, but they are non-mineral nutrients supplied mainly by air and water, not by the soil.

Application: Matching each option's element set against this classification shows which one is actually drawn from the soil in large quantity as a primary macronutrient set.

Cross-check — contrasting each set by value:

• Carbon, Hydrogen, Oxygen: obtained from air (as carbon dioxide) and water, not absorbed from the soil solution, so this set is not a soil macronutrient group at all.

• Nitrogen, Phosphorus, Potassium: absorbed from the soil solution in comparatively large quantities and are the elements most commonly limiting in agricultural soils — exactly the definition of the primary soil macronutrients.

• Iron, Manganese, Zinc: needed by plants only in trace amounts, which places this set among the micronutrients, not the macronutrients.

• Boron, Copper, Molybdenum: also required only in trace amounts, so this set likewise falls under micronutrients rather than macronutrients.

Result: Nitrogen, Phosphorus, and Potassium is therefore the set of macronutrients commonly found in and supplied by soil among the options given.