It was : B-refining oil Back then, standard oil managed to gain monopoly within the oil industry by buying all of the existing rival refineries and united it under the standard oil brand. This allow them to dominate the whole oil product that distributed in united states
You could check out this website:
https://newrepublic.com/article/126987/remaking-american-west
or this one:
http://www.ushistory.org/us/18e.asp
i'm not really sure what info you want tho..
Answer:
When faced with a question like this what you should do is read your answer for part A and then read the quote you chose for part B and see if the two add up to make a valid reasoning to support each other.