Statements B and C regarding soil are correct. Alluvial soils are very rich in chemicals like potash, phosphoric acid, lime and carbon compounds but are deficient in nitrogen and humus. Black soil is rich in metals such as iron, magnesium and aluminium. However, it is deficient in nitrogen, potassium, phosphorus and humus. Laterite soil is rich in aluminium and iron, but is deficient in potash, phosphoric acid, lime and nitrogen.