The correct answer is C. Freedom of Speech
Step-by-step explanation:
The purpose of a title is to summarize the content of a text, presentation, list, etc. According to this, the option that best completes the title is "freedom of speech" because all of the points listed are related to this right. In the case of Schenck v. the United States (1919), this was a legal case in which, the court determined freedom of speech could be limited if this right was used to obstruct the actions of government including causing insubordination in the military forces.
On the other hand, the Sedition Act established in 1918 made it illegal for citizens to use the right of freedom speech to speak badly about the government or the effort and military strategies used during the First World War. Finally, the imprisonment of Eugene Debts occurred in 1918 as Eugene Debts delivered a speech against the participation of the U.S. in the First World War, which was against the Sedition Act and other acts such as the Espionage Act. Thus, in the three legal cases or instances, the freedom of speech was the main issue and all of these controversies occurred during wartime.