Here's why:
* Metafiction is a literary device where the narrative self-consciously acknowledges its own fictional nature. It breaks the fourth wall and draws attention to the artificiality of the story.
* Option C exemplifies this by directly addressing the reader through footnotes. These footnotes comment on the story itself, acknowledging its constructed nature and potentially offering insights into the author's intentions or the fictional world's inner workings. This breaks the illusion of reality and draws attention to the text as a constructed narrative.
Let's look at why the other options are less clear examples of metafiction:
* Option A: A story told by a third-person narrator is a common narrative technique and doesn't inherently signal metafiction. While a third-person narrator can be unreliable or have a distinct perspective, this doesn't necessarily point to self-awareness of the fictional nature of the story.
* Option B: That presents plot backward is an interesting narrative choice, but it's more about structure than metafiction. It might be used to create suspense or offer a unique perspective, but it doesn't inherently comment on the story's artificiality.
While option B could potentially be used *within* a metafictional narrative, it's not a defining characteristic of metafiction in itself.