Which rhetorical device consists of two parallel parts with the second part reversed?

The rhetorical device that consists of two parallel parts with the second part reversed is known as chiasmus. This device is characterized by its structural symmetry where the first part of the phrase is mirrored in the second part but with a reversal of elements. An example of chiasmus is the phrase "Never let a Fool Kiss You or a Kiss Fool You," where the concepts are presented in a cross-structure, enhancing the emphasis and creating a memorable rhythm.

In contrast, alliteration involves the repetition of initial consonant sounds in closely placed words, serving more to create a musical quality than to establish a mirrored structure. Epiphora, on the other hand, is a rhetorical device in which a word or phrase is repeated at the end of successive clauses or sentences, often leading to a different effect focused on repetition rather than reversal. Antithesis juxtaposes contrasting ideas often within parallel structures, creating a clear comparison or opposition but without the mirrored inversion characteristic of chiasmus. Thus, chiasmus is specifically defined by this unique structure of reversal, making it the correct answer to the question.