In which years did the United States participate in World War I?

• A. 1914-1916
• B. 1915-1917
• C. 1917-1918
• D. 1918-1920

Answer: (C)

The correct response indicates that the United States participated in World War I during the years 1917 to 1918. Specifically, the U.S. entered the conflict on April 6, 1917, after maintaining a stance of neutrality for the initial years of the war. American troops were engaged in significant combat operations until the armistice was signed on November 11, 1918, effectively bringing an end to the hostilities. This timeframe is crucial in understanding the U.S. involvement, as it marks the period when American military forces played a pivotal role in supporting the Allied Powers against the Central Powers.

The other options suggest various periods during which the U.S. was either not involved or engaged in limited capacities prior to full entry into the war, which did not reflect the actual timeline of U.S. military involvement.