Who was allowed to immigrate to the U.S before WW1 ?

Between 1880 and 1910, 17 million immigrants arrived in the United States. By 1910, almost 15 percent of the population was foreign born. While earlier arrivals were largely British, Irish or German, most of these recent immigrants were from Eastern, Central and Southern Europe.

B, and I know this because I submitted it to a credible site and it read correct.