Which of the following best describes couplets?

A couplet is a prominent form of poetry that is defined as a pair of lines that are usually written in the same meter and rhyme together. This means that the end words of both lines typically share a similar sound, creating a musical quality and helping to reinforce the thematic or emotional connection between the lines. Typically, couplets are utilized in various poetic forms, including sonnets and narrative poems, to convey ideas succinctly or to create a memorable or impactful ending to a stanza. This particular definition aligns fully with the characteristics of couplets, making it the best descriptor among the options provided.

The other options do not accurately capture the essence of couplets. For instance, a unit of dialogue between characters refers to interactions in plays or prose, while a type of plot structure pertains to the arrangement of elements in a story. A resolution in a story is concerned with the conclusion or settlement of conflicts, none of which apply to the specific definition of couplets within poetry.