Final answer:
The best theory that reflects a psychologist's belief about a client's anxiety due to an innate desire to be perfect is that of humanistic theorists, specifically Carl Rogers's concept of the real self versus the ideal self.
Step-by-step explanation:
A psychologist believes that their client is anxious due to an ingrained desire to be perfect, which leads to intense self-judgment and distortion of true thoughts and feelings. This scenario best reflects the perspective of humanistic theorists, especially in the context of Carl Rogers's ideas about self-concept. Rogers theorized that incongruence between one's real self and ideal self can lead to feelings of unworthiness and anxiety.
According to Rogers and other humanistic psychologists, achieving congruence is essential for a healthy and productive life. They believe in the potential for good that is innate to all humans and focus on personal growth and self-actualization as key components of mental health. In contrast, psychodynamic theorists like Freud would focus on the unconscious conflicts between the ego, id, and superego as the source of anxiety.