The Greatest Roman Defeat Since Cannae, the Battle of Adrianople

The greatest Roman defeat since Cannae, the battle of Adrianople, was precipitated most directly by

A) the pressure of the Huns on the Visigoths.
B) mistreatment of the Visigoths by Roman officials.
C) the superiority of the Visigoth infantry over the Roman cavalry.
D) the attack of Attila the Hun.
E) a calculated abandonment of the defensive line along the Danube.