Choose the answer. which best identifies a subplot in julius caesar and explains its significance?

portia struggles to understand her husband's secrecy; it indicates that
brutus's behavior is out of the ordinary.

brutus and cassius struggle with antony and octavius for control of rome; it builds suspense about who will assume power next.

brutus struggles with the decision to join the conspirators or not; it builds suspense about whether or not the assassination will occur.
brutus struggles with calpurnia over whether they should inform caesar of the assassination plot; it builds suspense about who can and cannot be trusted.