D. is the closest answer. He is overconfident but Macbeth's fatal flaw is his unchecked ambition. He wants to be king no matter the cost and is willing to give up everything to have and keep the crown and throne. In the end, he still thinks he cannot be touched by any man born of a woman based on what the witches have told him. However, Macduff tells him that he was cut from his mother's womb and was not born in a natural way. Although Macbeth is afraid and no longer believes the witches, he still fights to the end and is killed.
I hope this helps.