iF thE populAtion oF thE EArth goEs on inCrEAsing At its prEsEnt rAtE, By thE miDDlE oF thE 21^stCEntury wE______All thE oil thAt DrivEs our CArs.
A．will usE up
B．will hAvE usED up
C．hAvE usED up
D．will hAvE BEEn using up