Maddie has volunteered to work with the underprivileged children who are participants in her professor's literacy project. she is hoping that her professor will take this into consideration when calculating her grade. maddie is expecting

The correct answer is "reciprocity." 

Reciprocity signifies a mutual exchange in which both parties benefit. In this case, Maddie is one party, and her professor is the other party. Since Maddie is volunteering to work with participants in her professor's study, her professor is benefiting from this free work. To make this a reciprocal relationship, Maddie would then have to receive a benefit, such as extra credit on her grade.