Answer-Which one of them is zonal soil forming process?

Humification is the process of formation of humus from plant residues, calcification is the process of accumulation of calcium or calcium salts in the soil which creates a layer in the lower level of soils thus create a zone, illuviation is a process of washing down of mineral salts from one layer to another i.e general process and horizonation is the formation of soil horizons and still this is very broad term.