When Studying Veterans Who Had Developed Combat-Related Posttraumatic Stress Disorder

When studying veterans who had developed combat-related posttraumatic stress disorder (PTSD) , Bremner and colleagues concluded that

A) a lower pain tolerance might be a precursor for developing the disorder.
B) a small right hippocampus might be associated with the development of the disorder.
C) a background of emotional abuse might be a precursor for developing the disorder.
D) a background of physical abuse might be a precursor for developing the disorder.