Answer:
Macbeth tells them... that Banquo has been the cause of all their misery. ... Macbeth wants Banquo killed under cover of darkness.
Explanation:
The murderers state that they are tired of their suffering and would do anything to bring an end to it. Macbeth seeks their assurance that they agree that Banquo is their enemy. The men do so and Macbeth tells them that he cannot be suspected of having had Banquo killed, since Banquo's allies will turn against him. Macbeth is angry that he has destroyed his own peace to become king, and that everything he has done will be to make Banquo's children kings. Therefore, he decides to kill Banquo and his only child, Fleance, so that he can prevent Banquo's line from ever taking the throne.