What Is the Relationship Between Stress and the Functioning of Your

What is the relationship between stress and the functioning of your body's immune system?

A) Research has failed to identify a real relationship between these two factors.
B) Increase stress compromises our immune system's ability to do its job fighting illness.
C) When our immune system fails we get sick, which causes us to experience more stress.
D) Stress causes us to get sick, which activates our immune system