Correct option is B
The equivalence of ferrous sulfate (FeSO₄ - 7H₂O) and gypsum for soil improvement depends on the nutrient content of the compounds. For improving soil, the amount of ferrous sulfate required to match the effect of 1 ton of gypsum is approximately 0.57 tons. This is due to the differences in their chemical composition and the way they affect soil properties like pH and fertility.