Final answer:
The necessary and sufficient conditions for therapeutic change in client-centered therapy are unconditional positive regard, genuineness, and empathy, as they create a supportive environment for personal growth.
Step-by-step explanation:
The necessary and sufficient conditions for therapeutic change according to client-centered therapy, as characterized by Carl Rogers, include three foundational elements. First, unconditional positive regard must be offered by the therapist, which signifies complete acceptance of the client regardless of their behaviour or thoughts. Second, genuineness (or authenticity) is required, where the therapist is sincere and transparent with their feelings during the therapy sessions. Lastly, empathy is crucial, where the therapist deeply understands and shares the feelings of their client. These conditions are seen as essential in developing a therapeutic environment in which clients are empowered to explore their feelings, which can lead to constructive personality change.