How do couplets typically function within a poem?

Couplets, which are pairs of lines that typically rhyme and have the same meter, often serve to encapsulate a particular idea or emotion in poetry. They can function effectively at the end of a stanza or a poem to provide resolution, making option B a suitable choice. In many traditional forms of poetry, a couplet can clarify or summarize the theme or message, effectively resolving any conflicts presented in preceding lines. This structural element allows the poet to bring closure to a problem or riddle introduced in the poem, creating a satisfying conclusion for the reader.

The other functions, while they may occur in poetry, are not the primary roles of couplets. Introducing new characters is more commonly associated with narrative poems rather than couplets specifically. Creating imagery involves the use of descriptive language, which can occur in various forms throughout a poem, but is not the defining characteristic of couplets. Developing a setting similarly depends on various poetic techniques and is not uniquely linked to couplets. Thus, the strength of couplets lies in their ability to provide resolution, making option B particularly fitting.