A Significant Military Threat to Western Europe in the Late

A significant military threat to western Europe in the late 8th century came from Scandinavia when:

A) the Abbasid Caliphate's re-conquest of Islamic territories.
B) the reappearance from the eastern Steppes of the Huns.
C) uprisings of Germanic tribes against Charlemagne's expansion.
D) Viking raiders attacked and plundered the British, Danish, and French coastal areas.
E) a renewed naval fleet from Carthage.