One Explanation for Dissociative Identity Disorder Is That It Results

One explanation for dissociative identity disorder is that it results from:

A) extreme trauma in childhood; the alter egos are created to embody the dissociated memories and emotions that are too painful for the primary personality to acknowledge.
B) abnormal brain structures, such as enlarged ventricles or smaller than average frontal lobes.
C) an extreme case of bipolar disorder, in which mood swings are so severe that "alternate personalities" seem to exist.
D) chemical imbalances in the levels of neurotransmitters such as glutamate, norepinephrine, and serotonin.