Answer:
Why did so many Germanic tribes begin invading the Roman Empire? They were fleeing the Huns, who had moved into their lands and began destroying everything. When they were running away from the Huns, the Germanic people moved through the Roman provinces of Gaul, Spain and North Africa.
Explanation:
I am pretty sure the answer is B
Talking to a person you do not know, an email to a business representative, and similar would be situations where someone would have to use formal language.