Which statement is true?

cassius is considered the protagonist because he orchestrates the conspiracy, which restores honor to rome.
cassius is considered both the protagonist and the antagonist because he kills caesar, a tyrannical leader, to save rome, but he also murders rome’s leader.
brutus is considered both the protagonist and the antagonist because he kills caesar, a tyrannical leader, to save rome, but also because he murders rome’s leader.
brutus and cassius are considered the antagonists because they assassinate caesar, the popular leader of rome, in cold blood simply to gain for themselves the power caesar and antony had.