_____ believed that there was not only a personal unconscious, but a collective unconscious as well.

• A. Sigmund Freud
• B. Alfred Adler
• C. Carl Jung
• D. Karen Horney

Answer: (C)

Verified step by step guidance

1. Identify the key figures mentioned in the problem: Sigmund Freud, Alfred Adler, Carl Jung, and Karen Horney.
2. Understand the concept of 'collective unconscious' which is a term introduced by Carl Jung. It refers to structures of the unconscious mind shared among beings of the same species.
3. Recognize that Sigmund Freud is known for his theory of the personal unconscious, which is different from the collective unconscious.
4. Note that Alfred Adler focused on individual psychology and concepts like inferiority complex, not the collective unconscious.
5. Remember that Karen Horney is known for her work on neurotic needs and did not propose the idea of a collective unconscious.