D, Explanation: Lady Macbeth remains firmly behind the plan to murder Duncan while her husband, in contrast, is far more hesitant. Choice a is incorrect. In Act I, she seems less kind and gentle than he does. Choice b is incorrect. Lady Macbeth begins thinking of the murder of Duncan as soon as she reads his letter about the witches' predictions, which include the remark about Macbeth being "king hereafter." Choice c is incorrect. While her husband recognizes the possible dangers of killing Duncan, Lady Macbeth does not foresee any problems.
