I'm 95% sure its D. hope it helps.
Answer:
it was promoted one of the largest migrations in US history.
rapid ecomic growth, buildings of railroads churches Banks.
the expansion of manufacturing service industry.
during the gold Rush California became an economic powerhouse at the end of the century
It would support commuting to work, transportation of foods to cities, transportation of raw materials to factories and produced goods out of factories, and transportation as a whole. Hope this helps.
