Answer:
D. the reality principle.
Explanation:
The complex nature of human personality is defined by Sigmund Freud by explaining three psychological components that are id, ego, and superego. The Id is the unconscious element which is driven by desires and pleasure. The superego is responsible for moral ideals which we learn from our parents and community. The component of ego works on reality principle and therefore molds the desire of id in a manner that is acceptable in the real world.