Which is true for rolling friction (µ_r), static friction (µ_s) and kinetic friction (µ_k) ?

${\mathrm{\mu }}_{\mathrm{s}}>{\mathrm{\mu }}_{\mathrm{k}}>{\mathrm{\mu }}_{\mathrm{r}}$

The rolling fiction is always less than sliding friction. Therefore, it is easy to move a heavy load from one place to another by rolling it over the surface instead of sliding it over the same surface.