D) Increased immigration in industrial areas.
By 1890, production by factories in American had grown eight times larger than what it had been before 1860. A large part of the workforce came from immigrants coming to the United States and settling in cities, looking for jobs. Ireland was one example of a country from which many immigrants came, looking for work in America, after the devastation of famine in Ireland (especially from potato crop failures).
I'm pretty sure syracuse was but I'm not sure.
