ACCorDing to thE pAssAgE, whAt wAs onE DisADvAntAgE oF rEsiDEntiAl ExpAnsion
A．it wAs ExpEnsivE.
B．it hAppEnED too slowly.
C．it wAs unplAnnED.
D．it CrEAtED A DEmAnD For puBliC trAnsportAtion.