Which foreign policy is based on building a strong military to prevent attacks from other countries?

a. deterrence
b. containment
c. isolationism
d. collective security

The Answer May be D, I mean my dad is a solider, but what does he know, Right? :D

imperial crisis leads to civil war.

roman forces withdraw from britain as goths attack rome.

odoacer topples romulus augustus

huns attack the empire and drive german peoples ahead of them.

i need !