I believe C. Is correct, hope this helps! :-)
C. I hope that this helps
C.) Illuminate the researcher's analysis and interpretation, I believe.
Answer:
d. expanded through migration across national borders and internal migration.
Explanation:
Late nineteenth-century witnessed widespread industrialization of the United States. It was a period of great economic boost which created a new wealthy class consist of wealthy merchants, industrialists, bankers, etc. Migration from the rural area and large scale immigrants provided the required labor forces for the increased production process.
