Final answer:
Macbeth's portrayal as a heroic figure in Act One sets up a stark contrast to his Tyrannical descent by Act Five, illustrating the play's themes of the corrupting power of ambition and the dramatic tension derived from his character transformation.
Step-by-step explanation:
It was important for Shakespeare to introduce the play with an account of Macbeth's performance in the battle against Macdonald to establish the character's attributes and foreshadow the themes of the play. Answer choice (c) Act One and Act Five serve to create dramatic tension by contrasting Macbeth's initial heroism with his later descent into tyranny is correct.
In Act One, we see a valiant Macbeth, described as "brave Macbeth" who "carved out his passage" until he faced Macdonald. His loyalty to King Duncan and his strength in battle make his eventual treachery to the king even more jarring. By Act Five, Macbeth's tyranny is evident as he descends further into madness and moral decay, a contrast poignantly showcased through his battle prowess. This shift from a heroic figure to a tyrannical ruler effectively highlights the corrupting influence of power and ambition, key themes of the play.