Final answer:
The therapy that uses classical and operant conditioning principles is behavior modification, which is grounded in the behaviorist approach.
Step-by-step explanation:
The approach to therapy that utilizes the principles of classical and operant conditioning is c. behavior modification. This approach is based on the behaviorist tradition in psychology, that focuses on modifying human behavior through reinforcement and association. Two forms of associative learning, classical and operant conditioning, are fundamental to this therapeutic approach. Classical conditioning involves learning by association, as shown in Pavlov's experiments with dogs, where a neutral stimulus becomes associated with a significant one, producing a behavior when the neutral stimulus is presented alone. Operant conditioning, on the other hand, involves learning based on the consequences of behavior, which can be reinforcement (positive or negative) or punishment, as extensively studied by B.F. Skinner.