A Sonnet has a final couplet when it has___________

A Sonnet has a final couplet when it has two lines at the end of the poem that rhyme with each other. These two lines usually serve to summarize or conclude the theme of the poem. Out of the given options, an octave refers to the first eight lines of a sonnet, while a sestet refers to the last six lines. Three quatrains are a type of sonnet that has three stanzas of four lines each, but it doesn't have a final couplet. Therefore, only the option that includes a final couplet is correct, which is the one that mentions the final two lines of the sonnet.