The Rf (retardation factor) value is the ratio of the Solute's distance travelled to the Solvent's distance travelled. Polar molecules will attract more toward adsorbent and cover smaller distance from the baseline. A has maximum Rf so it will less adsorbed on the adsorbent surface and travel faster and will be eluded first. C has minimum Rf value. So it is more strongly adsobred and less soluble in mobile phase.