Answer:
d. A few decades ago, China would not allow outsiders to see what it was doing.
Explanation:
Prior to joining the World Trade Organization (WTO), China wasn't open about it's economic activities or policy to other countries across the world. This simply means the Chinese government was very secretive about the happening in it's country and as such would not allow outsiders to see what it was doing or it's engagements.
However, joining the World Trade Organization (WTO) made them to be more open to other countries, which was a key factor for their unprecedented economic growth and development.
Hence, China was able to trade globally, capturing many markets and attracting foreign investment which boosted it's economy greatly.
Furthermore, China joining the WTO was at the detriment of the Western World (USA, Canada, UK, Germany etc) as it resulted in the loss of millions of jobs.
The dynasties created gunpowder, porcelain, and paper currency which would benefit the economy. Politically, people were able to move around the empires, many cities gained a higher population, thus leading to a social advancement.
