Final answer:
In client-centered therapy, developed by Carl Rogers, unconditional positive regard involves therapists offering themselves to the client unconditionally to foster self-worth.
Step-by-step explanation:
The concept in question relates to client-centered therapy, a psychological approach developed by Carl Rogers. In this therapeutic model, Rogers emphasizes that therapists should provide unconditional positive regard, genuineness, and empathy to enhance the therapeutic relationship and empower clients in addressing their issues. The aspect of making oneself available on an unconditional basis and increasing the client's feelings of self-worth is most closely aligned with the principle of unconditional positive regard, which entails the therapist accepting and valuing the client for who they are without judgment.
To answer the provided question, therapeutic: Making oneself available on an unconditional basis, increasing client's feelings of self-worth, the term that best fits this description is Offering self (Option D), which is a central component of Rogers' client-centered therapy.