Intellect was an important part of an empire and the Tang had many achievements in this area.
When comparing and contrasting an ancient government with the current US government I would recommend looking at the government of Ancient Athens, since Athens had a democracy like the US, except theirs was a "direct democracy," instead of a "representative" democracy--which would make this a good comparison point.
The economy was mostly based on farming, but other occupations were fur trapping, lumbering, shipping, slave trading, and iron mining. Once again, they were mostly based on farming though.
I think it goes like this
1) b
2) c