The trees of birnham wood moving toward dunsinane are of macbeth’s downfall.
a. clamorous
c. harbingers
b. developments
d. perturbations

In the statement "The trees of Birnham Wood moving toward Dunsinane are of Macbeth’s downfall.", the word that complete the sentence is harbingers. This is the main harbinger that Macbeth's destruction is unavoidable because of his terrible blemish. A reoccurring component in Macbeth will be Macbeth's evasion of his still, small voice and legitimizing his activities in light of his confidence in the powerful. Macbeth killed Duncan and Banquo in light of his faith in the witches' prediction.