Which of the Following Scenarios Depicts a Negative Effect of Using

Which of the following scenarios depicts a negative effect of using extrinsic rewards to motivate students?

A) Mario felt more confident about his abilities as an actor when the class applauded his performance.
B) Kitty was afraid to speak in front of the class even though she was interested in the topic that she had been assigned.
C) Fran loved to work on science projects until she entered the science fair and became more concerned about winning than enjoying the challenge.
D) Marvin enjoyed building sculptures with recycled "trash" despite the fact that he never displayed his work in public.