Role of inorganic nutrients plant growth and metabolism was first discovered by

Answer: Option A

The role of inorganic nutrients in plant growth and metabolism was first discovered by Knop.
Wilhelm Knop was a German agrochemist and co-founder of modern water culture. Nitrogen, Phosphorus, Sulfur, Potassium, Calcium, Magnesium, and Iron are identified as essential elements of plant nutrition by him along with Von Sachs.
They were the first to use standardized nutrient solutions in experimental plant physiology.