Dispersion of colloidal clay is caused by

Answer: Option A

Dispersion of colloidal clay is caused by Sodium.
Dispersion is a purely chemical phenomenon, driven by the balance of cations in the soil.
The inorganic or clay colloidal complex of soils occurs as too fine particles and the organic colloidal complex happens in the form of humus particles. The general balance between calcium and magnesium to sodium determines dispersion.