Answer:
The correct answer is 3: <u>The fear that American values were threatened by radical ideas. </u>
Explanation:
To begin with, the <em>Palmer Raids</em> were a series of raids that took place from November 1919 until January <em>1920</em>, which main purpose was <em>to capture and arrest</em> suspected <em>radical leftists</em>, mostly <em>immigrants</em> and especially <em>anarchists</em> and <em>communists</em>, so the deportation process would take place for them.
Secondly, <em>Sacco and Vanzetti</em> were two italian <em>migrant anarchists</em> who were convicted of murdering a guard and a paymaster in the year of <em>1920</em> in an armed robbery and went to trial.
And finally, the <em>Inmigration Act of 1924</em> was a United States federal law that <em>prevented immigration</em> from Asia, set quotas on the number of maximum immigrants that were allowed to inmigrate to the country.
In addition, by that period the<em> First Red Scare </em>was happening, so therefore that many Americans believed that bringing in more immigrants would allow radical ideas to take place over the nation and so the <em>xenophobia</em> spreaded around as well by that time.