A Court Is Listening Intently to Counsel's Argument Regarding Causation

A court is listening intently to counsel's argument regarding causation in a case arising in negligence.What must counsel have already firmly established to now be addressing the issue of causation for the court's deliberation?

A) the general standard that helps a court assess the defendant's negligence
B) that the defendant had a duty to avoid carelessness that caused harm to another
C) the reasonableness of an exacting standard of care imposed on activities
D) the identity of anyone who might reasonably be affected by another's conduct