Biuret content in urea should not exceed . . . . . . . . according to fertilizer control order, 1957

Answer: Option B

Urea is the most commonly used fertilizer as a source of nitrogen, but excess use of urea harms plants and also humans after consuming those products. Hence, the British Fertilizer Regulation in 1973 declared that urea used in agriculture should not have more than 1.5% biuret in it. Biuret is the toxic component of urea.