What year did the first female Marine enlist?

The first female Marine enlisted in 1918, marking a significant milestone in the history of the United States Marine Corps. During World War I, the necessity for additional personnel led to the recruitment of women into various roles, including clerical and administrative positions, to support the war effort. This pioneering step allowed women to serve in a military capacity, thereby laying the groundwork for future integration of women into the Marine Corps and other branches of the military.

The other options do not align with the historical timeline of women’s enlistment in the Marine Corps. The year 1910 predates the establishment of the Marine Corps Women's Reserve, while the years 1914 and 1920 were not notable for female enlistment in the Corps. Therefore, 1918 stands out as the correct year of enlistment, reflecting a pivotal change in military policy and gender roles within the Marine Corps.