Final answer:
The Palmer Raids targeted Communists and anarchists in the U.S. after WWI, led by Attorney General A. Mitchell Palmer and his assistant, J. Edgar Hoover, with widespread civil liberties violations ensuing.
Step-by-step explanation:
The Palmer Raids in the United States were a series of law enforcement activities that targeted groups deemed as radical threats to American society after World War I. The correct answer to the question about the group or groups targeted by the Palmer Raids is b) Communists and anarchists. These raids were organized under the leadership of Attorney General A. Mitchell Palmer and his assistant, J. Edgar Hoover, who later became the director of the Federal Bureau of Investigation (FBI). The Palmer Raids were characterized by a wide net that included not just Communist and anarchist political groups, but also labor organizers and various leftist organizations. Many of those targeted were immigrants, leading to deportations without trials, and numerous civil liberties violations.