It Has Been Suggested That Biofeedback Relieves the Pain of Tension

It has been suggested that biofeedback relieves the pain of tension headaches because it "teaches people to relax." What is the more likely reason?

A) The apparent relief of the patient's pain is the result of the sensory adaptation process occurring in the therapeutic session.
B) The biofeedback training gives patients a sense of control over their headache pain.
C) Biofeedback has a "numbing effect" because it affects the nerve endings in the somatic nervous system.
D) Patients experience a placebo effect because the headache pain returns once the biofeedback sessions are completed.