Which of the Following Is True About Chiropractors

Which of the following is true about chiropractors?

A) Chiropractors have less training and take fewer courses than allopathic non-specialized physician.
B) Recent research has shown that chiropractors were more successful in treating certain types of chronic pain such as lower back pain, neck pain and headaches.
C) Medical doctors and chiropractors maintain an adversarial relationship.
D) Chiropractors are federally licensed and regulated.