Answer:
intrinsic motivation
Explanation:
Intrinsic motivation is the motivation that one feels from internal rewards.
In this approach, a person does not look on external rewards to be motivated but instead is motivated to do things to explore, learn and see his/her potential.
Some examples of intrinsic motivation can be reading a book, painting and drawing for pleasure without expecting external rewards.
In the given question, the behavior of the person best describes the theory of "Intrinsic motivation." Because his motivation is not dependent on external rewards, i.e., grades.