Answer:
The sentence that best summarizes in an objective way the idea of the paragraph is "One way in which US businessmen acquired workers for their mines and mills was by offering contracts to groups of immigrants."
Step-by-step explanation:
The paragraph uses words with negative connotation to show bias against immigrants that came to America to work. It mentions "alien invasion", "huge armies of foreigners".
In order to change this paragraph into an impatial sentence, the correct option is "One way in which US businessmen acquired workers for their mines and mills was by offering contracts to groups of immigrants." since it does not use words that carry a negative effect.
The rest of the options are incorrect as they use bias against foreign immigrants. Examples: "inflicted huge armies of foreigners", "The hordes of unskilled laborers", "US businessmen didn’t care what happened to the America of our founders"