Answer: D. Andrew wants a good grade in calculus, so he completes extra practice problems.
Extrinsic Motivation entails the completion of a task or the exhibition of behavior due to outside causes like receiving a reward or avoiding a punishment. External rewards are known to be very good ventures in motivating an individual or a team to take on a new and more difficult challenge. Andrew completing extra practice exams so as to get a good grade is an extrinsic form of motivation because he is driven to complete extra practice exams solely because he needs a good grade.
The good grade here is therefore the motivating factor to his act and serves as a reward for taking extra practice exams. In the other options, the individuals mentioned are driven to do what they do as a result of their love and passion for it. This is not the case for Andrew as he does it for an eventual reward.