Answer:
The trees of Birnham Wood moving toward Dunsinane are harbingers of Macbeth’s downfall.
c. harbingers
Step-by-step explanation:
Harbingers is a person who tells about the approaching things. He tells this with any signal or sound. In the above sentence, the movement of the Birnam woods towards the palace was clearly denoting and telling of the approaching downfall of Macbeth.