ACCorDing to thE pAssAgE, primitivE oCEAn liFE BEgins to EvolvE into ComplEx orgAnisms ______.
A．in thE miDDlE oF DECEmBEr
B．whEn EArth is CrAtErED
C．At thE BEginning oF novEmBEr
D．whEn thE lAnD is still A liFElEss wAstE