David Is Undergoing Testing for a Suspected Psychological Disorder

David is undergoing testing for a suspected psychological disorder.His testing includes an injection of sodium lactate.The purpose of this injection is to 

A) treat David for obsessive-compulsive disorder, as he does not respond to other medications. 
B) see if David has major depressive disorder, in which case he will show an abnormal response to the sodium lactate in his HPA axis. 
C) see if David has bipolar disorder, in which case the sodium lactate will trigger a manic episode. 
D) see if David will respond with a panic attack, in which case he will probably be diagnosed with panic disorder.