Answer:
intrinsic reward
Explanation:
An intrinsic reward is a reward that comes from within one's self.
Here, Paula is satisfied with her grades but due to her own liking of the subject she takes the test. She does this because of own interest. This shows that she is motivated by an intrinsic reward.
If she were to take the test in order to get an A and prove to others her intellect this would be a case of extrinsic reward. The extrinsic reward is the reward done in order to attain external approval i.e., approval from someone other than one's self.
