During the middle of the 19th century, hundreds of thousands of Irish immigrated to the U.S. to avoid the potato famine and find better opportunities. Many of the Irish immigrants found an unreceptive American society where it was difficult to find work. When searching for a job, an Irish person might find help wanted ads that included the phrase "Irish need not apply." According to the passage, why were many Americans most likely so unreceptive to Irish immigrants? A. The Irish, in their large numbers, were looked upon as a drain on society, as they took jobs away from Americans. B. Most Irish immigrants were less qualified for jobs than immigrants of other nationalities. C. Americans were afraid of catching diseases from Irish immigrants. D. Most of the people that were already in the U.S. were non-European people who were biased against the Irish.