Final answer:
Psychologists use biofeedback mainly to help reduce tension headaches by allowing individuals to gain control over involuntary bodily processes through feedback provided by electronic measurements of neuromuscular and autonomic activity.
Step-by-step explanation:
Psychologists would most likely use biofeedback to help clients reduce c) tension headaches. Biofeedback is a method that relies on using electronic equipment to measure an individual's neuromuscular and autonomic activity, and then provides feedback through visual or auditory signals. This technique is grounded on the premise that biofeedback allows people to gain voluntary control over involuntary bodily processes. Researchers like Schwartz have applied it successfully to various conditions including high blood pressure, asthma, phobias, and notably, tension headaches.