Both a and c are correct, however I think that A would be the most correct answer in this case.
The Barbarian attacks on Romepartially stemmed from a mass migration caused by the Huns' invasion of Europe in the late fourth century. When these Eurasian warriors rampaged through northern Europe, they drove many Germanic tribes to the borders of the Roman Empire.
Ireland would be the correct answer!
Hope this helps!!!
David Wilmot prohibited slavery in the territory