Experiments Designed to Examine the Effectiveness of Various Treatments for Pain

Experiments designed to examine the effectiveness of various treatments for pain have found that

A) hypnosis is effective at reducing pain, but other psychological techniques such as imagery are not
B) hypnosis is not effective at reducing pain, but other psychological techniques such as imagery are
C) both hypnosis and other psychological techniques such as imagery are effective at reducing pain
D) neither hypnosis nor other psychological techniques such as imagery are effective at reducing pain