Answer:
B. Mass unemployment
Step-by-step explanation:
B. Mass unemployment.
While it was a problem in certain areas, it was not a consistent issue in the early 20th century compared to the other issues.
Mass unemployment refers to a situation where a large number of people are unable to find jobs because of a lack of economic activity. This was not an issue in the Early 20th Century, as economic activity was robust and the labor market was growing.
Therefore, child labor, dangerous working conditions, and long hours and little pay were all common problems with labor in the Early 20th Century.