Answer:
a and b only
Explanation:
The wave of European migrants coming to the US started during the colonial era until the mid-20th century. It was a large migrant phenomenon in which people from different countries and regions in Europe fled to America in order to escape from famines, economic crisis, wars, dictatorships, political repressions, persecutions, and other difficulties present in Europe during that time. In this sense, European migrants went to the US to find a better life and to escape from oppression and conflicts. Examples of this migration flux can be seen in the great migration from Ireland to the US that started in the mid-19th century after the burst of the great famine in Ireland, and also the many English Puritans that went to America in the 17th century escaping from religious and political persecution in England.
