Which of the following is NOT an element of a screenplay?

In a screenplay, essential elements that contribute to storytelling include character development, scene descriptions, and dialogue. Character development encompasses how characters grow and evolve throughout the story, which can significantly affect narrative tension and audience engagement. Scene descriptions provide the visual and contextual backdrop for the action, setting the tone and allowing readers or viewers to imagine the locations and events. Dialogue is crucial for conveying character interactions, advancing the plot, and revealing character motivations and emotions.

Costume design, while important in the broader scope of film production and visual storytelling, is not typically addressed within the screenplay itself. Screenplays focus on the narrative elements essential for telling the story, while costume design falls under the purview of the production team during the filmmaking process. Thus, costume design is the correct answer as it does not constitute an element specified within the screenplay's narrative framework.