At the turn of the twentieth century, the majority of the working poor lived
a. in rural areas.
b. in large homes.
c. in small towns.
d. in inner-city tenements.

D. in inner-city tenements.

From colonial times to the early twentieth century, the majority of Americans lived in the countryside. However, by 1890, 28% of Americans lived in urban areas and by 1920, more than half did. This change happened due to technological and industrial developments such as the steamboat, the locomotive, assembly-line production, the telephone, the telegraph, electricity and the automobile. This led to the rise of factories, which were usually located in cities. Factories were also the main source of work for the poor population, mostly European immigrants.

Okay the main difference is "power" is what they can do, "Authority" is was power they already have.