The most accurate conclusion is:
Prose poetry is written in complete sentences, while lyric poetry is not.
Prose poetry is characterized by its use of prose formats, meaning it is written in sentences and paragraphs rather than structured lines and stanzas. Lyric poetry, on the other hand, typically employs a more structured form with lines and stanzas, and it may not always be presented in complete sentences, focusing instead on musicality and emotional expression.