Final answer:
Macbeth hires two murderers to kill Banquo, with a third unexpected murderer appearing during the deed, symbolizing betrayal and mistrust.
Step-by-step explanation:
Macbeth hired two murderers to kill Banquo, but three murderers are present for the deed in Act 3, Scene 3, making the correct answer: A. Three; Two; Symbolizes betrayal within the group. The third murderer, whose presence is unexpected both by the audience and the other two murderers, heightens the theme of betrayal and mistrust that permeates the play. Just as Macbeth betrays Banquo, the presence of an additional murderer suggests mistrust within the conspirators themselves.