In Three of the Following Situations,positive Reinforcement Is Occurring

In three of the following situations,positive reinforcement is occurring. In which situation is positive reinforcement not occurring?

A) Sara begins behaving better in class when Ms. Jones allows her to spend extra time with her friends for exhibiting appropriate behavior.
B) Mr. Lewis consistently praises Mark for completing his independent seatwork on time,and Mark's work habits improve.
C) Ms. Villareal scolds Jeremy every time he speaks out of turn,but Jeremy's speaking out is increasing rather than decreasing.
D) Mr. Salazar smiles at Ellen every time she acts appropriately toward her classmates,but Ellen's social behaviors don't change.