prEvious rEsEArCh hAs EstABlishED thE lupinE wolF As thE ------- oF thE moDErn CAninE, But whEn AnD whErE humAns First DomEstiCAtED thE FormEr into thE lAttEr rEmAins unClEAr.
A．CompEtitor
B．Ally
C．sCion
D．prEy
E．(E) progEnitor