Read the passage from act 1, scene 3 of The Tragedy of Macbeth.

Macbeth. Stay, you imperfect speakers, tell me more:

By Sinel’s death I know I am Thane of Glamis;

But how of Cawdor? the Thane of Cawdor lives,

A prosperous gentleman; and to be king

Stands not within the prospect of belief

No more than to be Cawdor. Say, from whence

You owe this strange intelligence? or why

Upon this blasted heath you stop our way

With such prophetic greeting? Speak, I charge you. [Witches vanish.]



Banquo. The earth hath bubbles, as the water has,

And these are of them. Whither are they vanish’d?



Macbeth. Into the air, and what seem’d corporal melted

As breath into the wind. Would they had stay’d!



Banquo. Were such things here as we do speak about?

Or have we eaten on the insane root

That takes the reason prisoner?

Why does Banquo ask the rhetorical questions at the end of this passage?

to determine what Macbeth thinks of the prophecies
to see if the three witches will call out to him in reply
to explain that he does not believe in witchcraft or magic
to emphasize the strange disappearance of the three witches