That would be 4 Japan, where they dropped the two nuclear bombs in Nagasaki and Hiroshima
Answer: The empire became weak after numerous rebellions. The empire was in debt due to expensive building projects. The empire fell into decline after the death of a powerful leader.
They were able to unite because the Persian invasion of Greek mainland was a common threat for all, so they united to stop it. This was impossible before because Persia was not considered to be such a major threat.
The answer would be B) the Roman Empire, since they were the ones who established it, and the mongols came after the silk roads construction, alexander the great lived before the silk road, and many local governments also encompasses the romana
