Which of the Following Is True with Respect to the Overjustification

Which of the following is true with respect to the overjustification effect?

A) Fortunately, most parents intuitively recognize circumstances involving their children in which the overjustification effect is apt to occur.
B) Helping students to focus on the importance of achieving good grades tends to undermine the overjustification effect.
C) Hennessey and Zbikowski (1993) effectively immunized fourth graders against the overjustification effect by having older role models come to their classes to speak with them about the joy of learning.
D) Tang and Hall (1995) found that contingent reward (reward given only for good performance) can mitigate the overjustification effect.