Tbh I’m not sure this the right answer but C
It is B, Because Chicago was still a well populated area.
The correct answer is C. All of theses.
More than 30 million year ago massive extensions of swamp waters and marshlands were formed in Oklahoma. As the years went by these swamp waters were buried beneath soil, sand and gravel however, these water deposits later provided the state with natural resources such as coal, petroleum and natural gas. Thus they are or were called swamp treasures due to their multiple uses and the richness they gave to the state.
D. Vision
sorry if it’s wrong but I think this is the answer <33