What type of poetry lacks a regular meter or rhyme scheme?

The correct choice is free verse, which is characterized by its lack of a regular meter or rhyme scheme. This form of poetry allows the poet greater freedom to explore themes, images, and emotions without the constraints that structured forms impose. By not adhering to a fixed rhythm or pattern, free verse poetry can mimic the natural rhythms of speech and thought, which often results in a more personal and expressive style.

In contrast, the other options represent specific forms of poetry that do have established structures. A sonnet, for example, typically follows a strict rhyme scheme and meter, often consisting of 14 lines and adhering to specific formats such as the Petrarchan or Shakespearean form. A limerick is a humorous verse form with a distinct meter (anapestic) and a specific AABBA rhyme scheme. Similarly, a ballad generally has a consistent rhyme scheme and meter, often telling a narrative story in a rhythmic fashion. These characteristics differentiate free verse from the other poetic forms listed.