Which theorist developed interpersonal theory and the stages of interpersonal development?

Choice A reason: Jean Piaget is known for his theory of cognitive development, which includes stages such as sensorimotor, preoperational, concrete operational, and formal operational. His work focuses on how children acquire knowledge and logical reasoning, not interpersonal development. Choice B reason: Erik Erikson developed the psychosocial stages of development, which emphasize the impact of social experience across the lifespan. While his theory includes interpersonal elements, it is not specifically termed "interpersonal theory." Choice C reason: Abraham Maslow is best known for his hierarchy of needs, which outlines human motivation from basic physiological needs to self-actualization. His theory is motivational rather than interpersonal. Choice D reason: Harry Stack Sullivan is the originator of interpersonal theory, which posits that personality development and mental health are significantly influenced by interpersonal relationships. He outlined stages of interpersonal development and emphasized the role of social interactions in shaping personality.