What structure does not unfold chronologically?

The structure that does not unfold chronologically is non-linear. In non-linear storytelling, events may be presented out of sequence, allowing for flashbacks, parallel narratives, or other techniques that disrupt the traditional chronological flow. This can create tension, engage the audience's curiosity, and allow for deeper thematic exploration by juxtaposing events in a way that may not follow a straight timeline.

In contrast, linear structures present events in a straightforward chronological order, while circular structures often return to the starting point, completing a cycle rather than avoiding chronological flow. Sparse structures typically refer to minimalism in content or staging, which does not directly address the timeline of events. Thus, non-linear is the correct answer as it explicitly describes a narrative style that deviates from chronological order.