Answer:
C. newly arriving European immigrants
Step-by-step explanation:
During the Industrial Revolution, many people immigrated to America from Europe. At the beginning of the 20th century, most of the immigrants to the US were from Ireland, followed by Great Britain, Germany, and the rest of North-west Europe.
These people were often looking for any job to support themselves, as they flew from Europe because of the bad life conditions (for example, famine in Ireland). Therefore, there would more likely accept work which was less paid and done in bad conditions. This included the factory work.
More and more factories were being opened up in the cities, and they required a large amount of work. However, the conditions included long hours, an unsafe environment, and low wages. European immigrants were mostly the ones working these jobs, hoping to earn any money to start a new life.