in lonDon, how DoEs thEy solvE thE proBlEm oF thE trAFFiC CongEstion
A．thEy tAkE A ComplEtEly-FrEE Bus sErviCE.
B．thEy ExpErimEntED A vEry ChEAp Bus sErviCE.
C．pArt oF thE strEEt is For BusEs only.
D．thEy ClosED thE strEEts to CArs.