Concept:A fertilizer is a substance that supplies essential plant nutrients, especially nitrogen, phosphorus, and potassium.
Explanation:Galena is
PbS, the chief ore of lead, so it is not used as a fertilizer.
Bauxite is an ore of aluminium,
Al2O3⋅xH2O, used for producing the metal.
Emerald is a precious gemstone, a green variety of beryl, not an agricultural chemical.
Nitrochalk is calcium ammonium nitrate, often written as a mixture of
NH4NO3 and
CaCO3.
It is rich in nitrogen, a vital nutrient that promotes plant growth.
Because of its nitrogen content, nitrochalk is widely applied as an inorganic fertilizer on farmlands.
Answer:D. nitrochalk