The Ill Effects of Acidity in Subsoils Can Be Ameliorated

The ill effects of acidity in subsoils can be ameliorated by adding gypsum (CaSO₄^-2H₂O) to the soil surface.Which of the following most likely helps account for this effect?

A) The gypsum replaces hydrogen from colloids which moves down the profile and decreases the pH of the subsoil layers.
B) Calcium from the gypsum replaces hydrogen from colloids in the subsoil thereby increasing the soil pH.
C) Gypsum dissolves and leaches downward,increasing the Ca/Al ratio in the soil solution in subsoil layers.
D) Sulfate ions from the gypsum react with H ions in the subsoil to form H₂SO₄.
E) Gypsum stimulates root growth in the surface soil horizons.