Which Statement BEST Describes the Relationship Between the Immune System

Which statement BEST describes the relationship between the immune system and unipolar depression?

A) Dysregulation of the immune system leads to chronic inflammation, which causes depression.
B) The chronic stress caused by depression leads to immune system dysregulation and other health problems.
C) Researchers are unclear whether immune system dysregulation is a cause or a result of depression.
D) Immune system dysregulation is found in the majority of those persons with a biochemical imbalance and is believed to be a causative factor in depression.