Showed that people learn to behave in certain ways because of reinforcement.
a. john
b. watson
b. b f skinner
c. william james
d. sigmund freud

B.F. Skinner

Skinner was the founder of behaviorism, positing that one could take a subject as a blank slate and use, consistently, both positive and negative reinforcement to push the subject toward certain behaviors and away from others. If the reinforcement or consequence was positive, the behavior would be more likely to be repeated. If it were negative, it would be less likely to be repeated.

b. B F Skinner, why is there two option b's lol

I’m going to guess #4 since that seems pretty logical.