whiCh oF thE Following is truE ABout thE immunity to hivA．it is pArtly rEsistAnCE to thE mutAtion.
B．morEEuropEAns hAvE it thAn thE pEoplE on othEr ContinEnts.
C．it is thE rEsult oF outBrEAks oF thE plAguE.
D．it is A mutAtion thAt protECts whitE BlooD CElls.