The first answer is correct. Modern technology didn't make production costs higher. In fact, it made them lower. Technology had mostly positive effects on production.
The Persian Empire is the largest out of the options. It was larger than any previous empire and included modern day countries such as Iran, Afghanistan, Turkey, Iraq, Syria, Egypt, parts of Greece, and most of the near east. It successfully created a governmental administration by which road systems, organized civil systems, and an highly organized army allowed the civilization to flourish from 550 BCE until 330 BCE.
They make some of the changes to the government
The most recent group to invade northern India would be The Huns.
