Answer:
a. Ambition and betrayal
Step-by-step explanation:
Acts 1 through 2 shows the beginning scene of Julius Caesar and the plans to murder him by Brutus, incited by Cassius. But for Brutus, it is for the good and safety of Rome that he's agreed to be a part of this plan. These two acts cover the scenes where Antony had offered the crown to Caesar and he had refused thrice. But with the growing crowd pressure, it is believed that Caesar will eventually agree to be crowned king. And Brutus believes that with the more power given to Caesar, he might misuse his power and become vain. And so, in order to save Rome from such takeover, he's decided to become an accomplice with the rest who wanted Julius Caesar dead before he's crowned. These two acts portrays the ambitions of both Brutus and Caesar - one for the future of Rome and the other for his own ambition. It also shows the betrayal by Brutus, who doesn't have any personal hatred for him but just his duty for the welfare of Rome.