Historians Now Refer to the Period from 284 to 610

Historians now refer to the period from 284 to 610 c.e.as Late Antiquity because:

A) while the western half of the empire had fallen,the eastern Roman Empire was still flourishing.
B) it is a period with its own themes and developments,not wholly Roman and not yet medieval.
C) all Roman institutions had been abandoned or destroyed.
D) the term Dark Ages refers only to the literature of the period contrasted with classical literature.
E) while the eastern part of the empire had fallen,the Western Roman Empire was still flourishing.