Events in late Han China and the late Roman Empire show that the decline of a civilization, whether temporary or permanent,
a. follows inevitably from centralized, unrepresentative government.
b. results from undue dependence on slavery.
c. results from a lack of religious conviction.
d. is not simply the result of attack by outside invaders.
e. results from social rebellion in which the poor attack the rich and destroy their institutions.
Answer: D