thE most suCCEssFul trEAtmEnt DEsCriBED in thE pAssAgE wAs A sErum prEpArED From ______.
A．thE BlooD oF pAtiEnts who hAvE BEEn stung
B．poison ExtrACtED From BEEs
C．CrushED BoDiEs oF BEEs
D．A plACEBo AnD A CrushED-BoDy ExtrACt