The correct option is D Differential adsorption of the various substances on the stationary phase
Column chromatography:
Main principle of column chromatography is differential adsorption of the substance on the solid phase.
The mixture adsorbed on an adsorbent is placed on the top of the adsorbent column packed in a glass tube.
An appropriate eluent, which is a liquid or a mixture of liquids is allowed to flow down the column slowly.
Depending upon the degree to which the components are adsorbed, complete separation takes place.