Solution:(a) Sigmund Freud proposed the Psychoanalytic theory, which emphasizes unconscious mind dynamics, early childhood experiences, and conflicts between innate drives and societal norms.
(b) Behavioural theory, linked to John B. Watson, highlights observable behaviours and their relationships with environmental stimuli, emphasizing learning through conditioning.
(c) Carl Rogers, a prominent figure in Humanistic theory, focused on selfactualization, personal growth, and a positive view of human potential.
(d) Cognitive theory, associated with Albert Bandura, explores mental processes like thinking, memory, and problem-solving, emphasizing the role of observational learning and self-efficacy.