In the play's final act, why does Antony describe Brutus as the noblest Roman of them all?

AAntony considers Brutus to be a traitor and a criminal; his words are sarcastic.
BAntony knows that Brutus was the only conspirator who acted for the good of Rome.
CAntony was once Brutus's best friend.
DAntony is acknowledging that Brutus came from a very wealthy and aristocratic Roman family.

Verified Answer :

b. Antony knows that Brutus was the only
conspirator who acted for the good of Rome. Brutus like his power
believed in the power of the Roman Senate.
Caesar was now a threat to that institution.  Even though he and Caesar were friends, he
sided with the conspirators to preserve the Senate.