Final answer:
Carl Jung believed that self-realization is best served by finding a balance between extroversion and introversion, integrating these aspects to harmonize one's personality.
Step-by-step explanation:
According to Carl Jung, a balance between extroversion and introversion is vital for achieving self-realization. Jung posited that the ideal path towards self-realization involves integrating both extroverted and introverted attitudes. Extroverts gain energy from social interaction, while introverts find energy in their inner reflections. The focus of analytical psychology, which Jung developed, is to reconcile the opposite conscious and unconscious forces within an individual's personality, a process that is ongoing well into the second half of life. By harmonizing these aspects of personality, a person moves toward self-realization, in contrast to remaining fixed in the archetypes of the collective unconscious. Thus, the correct answer to the question would be C. balance between extroversion and introversion, which best serves the goal of self-realization according to Jung.