I believe the correct answer is B. sets a single syllable of text to many notes.
Melismitic chant is the style in which single syllable of the text is matched to many notes, as opposed to the syllabic music which has only one note for on syllable. The single syllable sung with many notes while moving between several different notes in succession is called melisma. Melismatic chant is used to induce a hypnotic trance in the listener which is way it was often used for early mystical initiation rites and religious worship.