In Looking Through Some Medical Records You Find That There

In looking through some medical records you find that there is a strong relationship between depression and chronic pain: the stronger the physical pain that people report, the higher their scores on an inventory that measures depression. Which of the following conclusions are justified?

A) Depression tends to produce chronic pain.
B) Chronic pain tends to produce depression.
C) Both chronic pain and depression result from some unknown third factor.
D) any of these statements could be true