Posttraumatic stress disorder (PTSD) as the name indicates it the disorder that is developed after a serious traumatic stress or experiencing an event that involves threatened death, murder or witnessing a violent situations like military combat.
Hence the option d is not correct.
Dissociative Identity Disorder (DID) is also called multiple personality disorder. This means that the individual behaves in two or more distinct personality states. This is also characterized by inability to recall personal information. The alternative identities are very different from the original character.
Hence the option c is not correct.
Dissociative amnesia is one of the types of dissociative disorder that is characterized by the failure of memory functioning and unable to bring to mind the previously stored information. This is mainly associated with failure in recalling the autobiographical information.
Hence the option b is not correct.
Depersonalization disorder is characterized by sudden change in the behavior and in a strange way like feeling detachment from the body and watching herself etc.
Hence the correct option is .