In Which of the Following Instances Is the Teacher Most

In which of the following instances is the teacher most likely to be held liable?

A) Two students begin to speak to each other hostilely. The teacher tells them to stay away from each other. Even though they appear to have calmed down during class, they begin fighting as soon as they leave class.
B) While a teacher is circulating through the classroom assisting students with their work, a student unexpectedly jumps out of her seat to show a friend a dance move. In doing the move, she dislocates her shoulder.
C) A teacher ignores two students who begin to wrestle playfully, and one of them breaks a wrist.
D) A student enters the teacher's class very angry about a fight he has just had with his father. In his emotional state, he puts his fist through a window, cutting his hand.