During World War I, the American Protective League was

A) a regiment of highly trained soldiers.
B) the President's new security service.
C) a group of volunteers in the American Expeditionary Force.
D) a network of volunteers that aided in censorship and surveillance.

American Protective League

A volunteer organization in the United States during World War I that worked with federal law enforcement agencies to identify suspected German sympathizers and enforce loyalty to the United States.

Censorship And Surveillance

The practice of monitoring and controlling information and communication, restricting access to materials deemed objectionable or a threat by authorities.