The correct answer is D. podsolisation.
Podsolisation is a type of soil formation that occurs in acidic, poorly drained soils. It is characterized by the accumulation of organic matter in the upper layers of the soil, the leaching of iron and aluminum from the upper layers, and the formation of a bleached, sandy A horizon.
Salinisation is the accumulation of salts in the soil. It can occur when water evaporates from the soil, leaving behind the salts that were dissolved in it. Salinisation can make the soil difficult for plants to grow in.
Gleisation is a type of soil formation that occurs in waterlogged soils. It is characterized by the accumulation of organic matter in the upper layers of the soil, the reduction of iron and manganese, and the formation of a grey, mottled B horizon.
Calcification is a type of soil formation that occurs in alkaline soils. It is characterized by the accumulation of calcium carbonate in the soil. Calcification can make the soil difficult for plants to grow in.