The correct answer is B. Factory jobs in American cities.
Step-by-step explanation
The United States has been one of the most frequented destinations by European immigrants since the Colony. This has caused that during the first half of the nineteenth century about five million European immigrants arrived and during the second half of the same century more than twenty-five thousand people arrived. They were mainly German, Irish, Italian, English Austro-Hungarian and Russian. This massive displacement originated from a pull factor (positive condition of another country, which attracts immigrants and makes them leave their country of origin) that was the job offer in American factories in addition to living conditions which were contrary to the great crises that were in Europe. So, the correct answer is B. Factory jobs in American cities.