The correct option is D.
Lady Macbeth has developed a new habit of 'sleeping walking' and in Act 5, scene 1, a doctor and a gentlewoman was discussing this new development in Lady Macbeth's house in the middle of the night, when Lady Macbeth entered the room where they are, in a trance state, bemoaning the death of Lady Macduff and Banquo and telling them that she sees blood in her hand. This implies that she knows something about the murder and she is regretting her part in it.