Research on the Causes of Anxiety Has Demonstrated That

Research on the causes of anxiety has demonstrated that:

A) women exhibit anxiety disorders more often than men do
B) patients with a history of panic attacks show a lower concentration of GABA than controls without a history of panic disorder
C) genetic factors may create a vulnerability to anxiety disorders
D) both patients with a history of panic attacks show a lower concentration of GABA than controls without a history of panic disorder AND women exhibit anxiety disorders more often than men do
E) all of these