[单选题]
10.10: A particle trav xkz1q(* cl 7ajtkpu17vgb7x3ek xpex s we79u525l:romg9njiu4ri n:b -g) 5rls at a constant speed around a circular path of radius $R$, if the particle makes one complete trip around the entire circle, what is the magnitude of the displacement for this trip?