Answer:
Constancy
Step-by-step explanation:
Among the different conceptual blocks that restrain us from being creative and change, constancy is the one indicating that once we have found out how to solve a problem, we stick to that solution to solve other similar problems. This is when it becomes hard to set that solution aside and go for a different one. In this case, Harry does not want to change his study method even though it has not worked well for him on his last exam.