Final answer:
The theory that best describes personality development in client-centered therapy is Humanistic theory by Carl Rogers. This theory emphasizes self-actualization, free will, and individual potential, in contrast to the psychoanalytical approach of Sigmund Freud and the behavioral theory of B.F. Skinner.
Step-by-step explanation:
The theory that best describes personality development in client-centered therapy is C) Humanistic theory by Carl Rogers. Carl Rogers, along with Abraham Maslow, were pioneers in the humanistic approach to psychology. They focused on the growth potential of individuals and the drive towards self-actualization. This approach is distinctive from other theories as it emphasizes free will, self-determination, and the desire to achieve individual potential.
In contrast to the psychoanalytic perspective of Sigmund Freud, which focuses on the impact of early psychosexual development on personality, and the behavioral theory by B.F. Skinner, which suggests that behavior is shaped by environmental reinforcements and consequences, the humanistic approach considers a person's subjective experience and innate drive for personal growth as central to personality development. Client-centered therapy, a part of humanistic psychology, posits that a supportive and understanding therapeutic environment can facilitate an individual's natural tendency toward self-improvement and self-understanding.