Answer:
a. he consults well-known, credible sources in his research.
Explanation:
The attempt to be objective is trying to search for as many sources as possible, experts in the matter and trying to portray both sides of the story, this way objectiveness can be achieved, by writting and consulting credible well-known sources is part of that job.
In the 1860s, most factories were located in the North of the United States, mostly because the South was largely agricultural and remained this way for many years.
I'm pretty sure it's c but don't quote me on it
Vasco de Gama was the first explorer to reach India
