Final answer:
The statement in question could address different parties depending on context: it could be the reader, the reader's friend, the reader's enemy, or the speaker themselves.
Step-by-step explanation:
The person being addressed in the statement 'You know perfectly well what is the matter with you_________You are mentally deranged. You suffer from a defective memory.' could be interpreted in different ways depending on the context of the material from which the statement is taken. Without additional context, this could be addressing the reader (2), the reader's friend (3), the reader's enemy (4), or even perhaps the speaker themselves (1). However, based on the given excerpts and literary pieces, it is most likely that the speaker is addressing either the reader or a character within the story they are a part of, depending on whether the text is breaking the fourth wall or if it is in the context of a dialogue between characters.
For example, in the excerpt that talks about the unreliable narrator, the matter being referred to could be the narrator's misinterpretation of her room as a former playroom, contrasting with a more realistic realization that it might be something more akin to a cell, given the bars on the windows. This would suggest that the speaker could be addressing the character as part of the story's interior dialogue.