jEAn wAgnEr’s most EnDuring ContriBution to thE stuDy oFAFro-AmEriCAn poEtry is this insistEnCE thAt it ________ in A rEligious, As wEll As worlDly, FrAmE oF rEFErEnCE.
A、is to BE AnAlyzED
B、hAs BEEn AnAlyzED
C、BE AnAlyzED
D、shoulD hAvE BEEn AnAlyzED