Research on Relaxation Training Versus Biofeedback Has Indicated That

Research on relaxation training versus biofeedback has indicated that

A) relaxation therapy is much more effective at treating stress,anxiety,and physical ailments than biofeedback.
B) biofeedback is much more effective at treating stress,anxiety,and physical ailments relative to relaxation therapy.
C) these techniques are equally effective in reducing stress and treating anxiety as well as other physical ailments.
D) neither one of these techniques is overly effective at treating stress,anxiety,and physical ailments.