What is the exposition in 'The Tell-Tale Heart' by Edgar Allan Poe?

In "The Tell-Tale Heart," the exposition introduces the unnamed narrator who insists on their sanity while describing an obsession with an old man's eye, which they find repulsive. The narrator explains their meticulous planning to kill the old man, driven by a profound aversion to the eye rather than any personal animosity. This sets the stage for the ensuing conflict and the narrator's descent into madness, establishing the story's dark and suspenseful tone.