Jean Wagner's most enduring contribution to the study of Afro-American poetry is his insistence that it ________ in a religious, as well as worldly, frame of reference.
句意：让·瓦格纳坚持用宗教和世俗的参照系来分析诗歌，这对美国黑人诗歌研究的贡献旷日持 久。本题考查insistence的用法，insistence后接省略to的不定式，表命令、要求等。结合句意，选择C。