Largest Immigrant Group in Late 19th Century

Between 1865 and 1898, the United States experienced a significant influx of immigrants from various parts of the world, which transformed the social, economic, and cultural fabric of the nation. Many of these immigrants were drawn by the promise of industrial jobs, but they also faced numerous challenges, such as discrimination and harsh living conditions. Of the following groups of immigrants, which one was the largest group in the late 19th century, particularly in the 1880s, and significantly influenced urban centers through labor movements and cultural contributions?