iF thE populAtion oF thEEArth goEs on inCrEAsing At its prEsEnt rAtE, By thE miDDlE oF thE 21^st CEntury 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