The most concentrated fertilizer used for nutrient supply is

Answer: Option C

The most concentrated fertilizer used for nutrient supply is anhydrous ammonia.
Ammonia (NH₃) in anhydrous form, that is without water, is an efficient and widely used source of nitrogen fertilizer. It has the highest content of nitrogen at 82%. Under atmospheric temperature and pressure, it is a colourless gas with a sharp and penetrating odor. It is easily accessible to farmers and simple to implement. However, it can be dangerous if not handled properly.