How were the inca rulers able to maintain control over their vast empire

i believe the answer is d.

citizens get the vast majority of their political and governmental information from the media, which includes television, print journalism, radio, and now the internet. the media play an important role in connecting people to government.

the correct answer is:   the domino theory states that if one country in a region came under the influence of communism, then the surrounding countries would follow in a domino effect.