One Key Factor of Posttraumatic Stress Disorder Is

One key factor of posttraumatic stress disorder is

A) exposure to traumatic events where a person experienced, witnessed, or confronted an event involving actual or threatened death or serious injury to oneself or someone else.
B) symptoms lasting two days to four weeks.
C) attempts to separate from persons related to the dramatic situation resulting in separation anxiety disorder.
D) development of social phobia.