Final answer:
B.F. Skinner, a behaviorist psychologist, is credited for developing operant conditioning and advancing the field of behaviorism through his influential research.
Step-by-step explanation:
Credit for the development of operant conditioning goes to a psychologist named B.F. Skinner, who was a leading figure in the field of behaviorism. The correct choice from the provided options is (b) Behaviorist; B.F. Skinner. Skinner's research focused on how behaviors are influenced by their consequences, specifically through reinforcement and punishment.
He developed the operant conditioning chamber, commonly known as the Skinner box, which was a pivotal tool in the study of behavior modification. Skinner's work established behaviorism as an objective science, emphasizing the study of observable behaviors over unobservable mental processes.