Answer:
Intrinsic motivation
Explanation:
Intrinsic motivation is an internal behavior reward. This is the motivation that arises from inside for a work to engage in. It is the natural procedure that satisfied a person internally and personally from both sides.
It is opposite to the extrinsic motivation. Extrinsic motivation is when a person is rewarded by outer sources to do work. So that William was intrinsically motivated for doing work.