Which most directly led to the rise of mass entertainment during the late 1800s?

The rise of mass entertainment in the late 1800s was primarily driven by the expansion of urbanization, increased leisure time for the working class, and advancements in technology such as the phonograph and motion pictures. The proliferation of vaudeville shows, circuses, and amusement parks provided accessible entertainment options for the growing urban population. Additionally, the advent of print media and advertising helped to popularize these forms of entertainment, making them a staple of American culture.