Which of the Following Is NOT True

Which of the following is NOT true?

A) Tang and Hall (1995) found that contingent reward can mitigate the overjustification effect.
B) Wimperis and Farr (1979) found that subjects who received a reward only if they performed well outperformed subjects in the noncontingent condition, thus avoiding the overjustification effect.
C) Being rewarded regardless of how well you perform may be the root cause behind the overjustification effect.
D) Research has found that lack of reward influences the overjustification effect.