In Act V of The Tragedy of Macbeth by William Shakespeare, why does Macbeth believe that Malcolm cannot harm him?

He knows that he is a much better swordsman than Malcolm.

He knows that Malcolm would not be able to approach the castle from Birnam Wood.

He is overconfident in his ability to fight against Malcolm and his army.

He believes the witches’ prophecy that no man born of a woman can harm him.