Final answer:
The correct answer is option b) Environmental degradation and displacement of Native Americans.
Step-by-step explanation:
A negative consequence of building factories and railroad lines in nineteenth century America was environmental degradation and displacement of Native Americans. The rapid industrial expansion that included developments such as the steel manufacturing, the telephone, and the light bulb, led to significant environmental impacts due to the mass extraction of natural resources and pollution from factory emissions.
Moreover, the construction of the transcontinental railroad and settlement in the West led to the forceful removal and displacement of Native American communities from their ancestral lands, disrupting their way of life and causing profound cultural loss.