The correct statement among the following, for a "chromatography" purification method is :

A

Organic compounds run faster than solvent in the thin layer chromatographic plate.

B

$$R_f$$ is an integral value.

C

$$R_f$$ of a polar compound is smaller than that of a non-polar compound.

D

Non-polar compounds are retained at top and polar compounds come down in column chromatography.