Answer:
Ego
Step-by-step explanation:
Id, ego, and superego are terms introduced by Sigmund Freud, the father of psychoanalysis. Each of these terms refers to a part of the human personality.
The id is the instinctual component of personality, the source of bodily needs, emotional impulses, and desires. It seeks satisfaction.
The ego is the component of our personality that aims to please the id in realistic ways we will benefit from.
The superego is the third part of our personality. It acts as a self-critical conscience created according to the principles we are taught by the society we live in, especially our parents and teachers. It is the ethical component that provides moral standards that the ego follows.
Based on this information, we can conclude that the given scenario is a representation of the ego. Will wants to break the school record in cross-country. He sees an opportunity to do so, but that opportunity involves cheating. He knows that cheating is wrong - that is what he was taught. Cheating is something that is frowned upon by society and most likely his family as well. This is why he knows it's a bad thing and would feel bad if won that way. This is the principle that is a part of his superego. He acts upon that principle and decides to stick to the course and run as fast as he can. Will's ego, which follows the principles of his superego, is responsible for his decision.