Answer: C) The superego
Explanation: According to Freud's psychoanalytic theory of personality, the superego works against the id by encouraging behaviors which are in line with societal norms. The superego tends to make the ego behave morally based on the teachings of parent and the society at large.
Carl's restrictions on taking of alcohol in public because it's not socially acceptable is caused by his superego. According to the psychoanalytic approach, the superego is responsible for this kind behaviors.