Pools were agreements between railroad corporations to divide the business in a given area and share the profits. Many companies formed these pools in order to avoid competition by dividing business in a particular area. Efforts to regulate the monopolizing practices of railroad corporation then first came in the form of action by the supreme court.
Lets use the process of elimination in your question
It can't be A because Lincoln wanted to end the war and have the Southern states join the union as quickly as possible and free all the slaves
It is most likely B because he doesn't really do much to punish he wants to end the war
C and D could easily be eliminated
The correct answer is A. They had elaborate trade networks.
Explanation
Trade networks are a form of the economic relationship between human communities in which products or services are exchanged for other goods or services or exchange currency. With the arrival of the Europeans in America, it was discovered that the native communities had a very elaborate network of commercial relations that allowed them to exchange their products with the other tribes in different parts of the wide American territory, from where they could obtain different products such as sea fish, river fish, the meat of domesticated animals, fruits, and other products of agriculture. So, the correct answer is A. They had elaborate trade networks.
The surface area would be 234