The correct option is D. Immigrants primarily came from Ireland and Germany in the mid 1800s.
Between 1820 and 1860 a wide majority of immigrants came from northern and western Europe. The potato famine in Ireland which uccured from 1845 to 1847 resulted in the immigration of a large numbers to the United States. Furthermore, the unsuccessful 1848 Revolution in Germany led to a considerable emigration to the United States.