What Is the Best Explanation to Offer When the Mother

What is the best explanation to offer when the mother of a chronically ill teenage patient asks,"Under what circumstances would he be considered incompetent?"

A) "When you can provide the court with enough evidence to show that he is not able to care for himself safely."
B) "It is not likely that someone his age would be determined to be incompetent regardless of his mental condition."
C) "He would have to engage in behavior that would result in harm to himself or to someone else; like you or his siblings."
D) "If the illness becomes so severe that his judgment is impaired to the point where the decisions he makes are harmful to himself or to others."