A. The witches told Macbeth that even though he would not be king, his children would inherit the throne.
B. The witches are powerful, and Macbeth is afraid they will do something to harm the king.
C. The witches told Macbeth that he would be a great hero even though he would be killed in battle.
D. The witches told Macbeth that he would be king, and he is worried about his role in making the prediction come true.
The answer is D.