Which of the Following Is True About Bipolar I Disorder

Which of the following is true about Bipolar I Disorder as defined in the DSM-5?

A) The diagnostic criteria for a Major Depressive Episode is the same as it is in Bipolar II Disorder.
B) Manic episodes are severe enough to cause impairment in social and occupational functioning.
C) A history of a Major Depressive Episode is required for diagnosis.
D) Both a. and b.
E) All of the above