Which of the Following Best Illustrates the Application of Operant

Which of the following best illustrates the application of operant conditioning principles in health psychology?

A) A person with peptic ulcers undergoes relaxation training.
B) A person with a fear of the dentist undergoes systematic desensitization.
C) Family members of a chronic pain patient are instructed to ignore the patient's complaints and reinforce the patient's attempts to become more physically active.
D) A person with hypertension is taught to imagine, during highly stressful times, a calming scenario that he/she has created with his/her health psychology professional.