From what i can actually read it look to be correct.
China joining WTO is a major step in its economic development. This is because it enabled China to capture many markets and attract foreign investment which contributed to the loss of millions of jobs in the Western World. As a result of opening its borders, China experienced unprecedented economic growth
I'm pretty sure A is the secondary source. All of the others come directly from the source/person, but an interview is getting someone else's view.
The ancestors of living Native Americans arrived in what is now the United States at least 15,000 years ago, possibly much earlier, from Asia via Beringia. A vast variety of peoples, societies and cultures subsequently developed.
