Final answer:
The National Civil Liberties Bureau was established to challenge government policies against wartime dissent, so it was not a method used to control American dissent during World War I.
Step-by-step explanation:
The U.S. government employed several methods to control American dissent against the war effort during World War I. Among these were propaganda campaigns, repressive legislation such as the Espionage Act and the Sedition Act, and the creation of the Committee on Public Information to disseminate pro-war information. The National Civil Liberties Bureau, however, was not used to control dissent; rather, it was established to challenge the government's policies and advocate for civil liberties. It later evolved into the American Civil Liberties Union (ACLU). Therefore, the correct answer to the question 'What of the following was not used to control American dissent against the war effort?' is C. National Civil Liberties Bureau.