Which of the following is not an anxiety disorder?
a) panic disorder
b) obsessive-compulsive disorder
c) bipolar disorder
d) posttraumatic stress disorder

You have to think about whether people would likely experience anxiety or some sort of fear having these disorders.

In panic disorders and posttraumatic stress disorders fear and anxiety is the central part of the disorder. In the bi-polar disorder times of feeling extremely happy are interrupted by times with depression and anxiety - so anxiety is also a symptom of this disorder.
 
So the correct answer is B) obsessive-compulsive disorder - this disorder is not directly related to anxiety!

Bis correct you

Post the graph so people can answer