The correct answer and lines in the play that support the mentioned fact are "Get on your nightgown, lest occasion call us, / And show us to be watchers."
Of all the mentioned options, this is the choice that conveys the idea that Lady Macbeth knows she and ther husband must appear ignorant of the king's murder. In these lines from Act 2, Scene 2, Lady Macbeth is literally telling her husband to get in his pijamas to appear innocent in case someone sees them awake so they will not think they were involved in the murder of Duncan. The sentence also shows how manipulative and cunning Lady Macbeth can be.
