Final answer:
The main idea of 'The Tell-Tale Heart' is the exploration of guilt and madness within the protagonist, leading to his confession to murder. The internal conflict resulting from his conscience and deteriorating mental state are central to the story's theme.
Step-by-step explanation:
The main idea of the story 'The Tell-Tale Heart' by Edgar Allan Poe is c) It explores the themes of guilt and madness. The narrative delves into the psychological complexities of the protagonist, who is also the narrator of the tale. The narrator commits murder and is driven to confess the crime because of the overwhelming guilt, illustrated through the metaphor of a beating heart that the protagonist believes to be the heart of his victim. The short story vividly portrays the conflict between the narrator's attempt to demonstrate sanity and the irrational actions that ultimately lead to his undoing.
The heart of this gothic story rests on the internal conflict and personal torment that stem from the narrator's conscience. This internal struggle is a classic example of the theme of guilt, as the narrator is haunted by his actions and the perpetual beating of what he perceives as his victim's heart. The theme of madness is equally prominent, as the narrator's mental state unravels, culminating in his frenzied confession to the crime, which reveals his deteriorated sanity.