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

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