Which is the most complete explanation of why people immigrated to the United States in the late 1800s and early 1900s?

People immigrated because of both push factors, such as poverty, persecution, or lack of opportunity in their home countries, and pull factors, such as jobs and the chance for a better life in the United States. Choice A, a combination of push and pull factors, is more complete than choice D, which names only employment opportunities.

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