Final answer:
Women began working in Washington offices as clerks in significant numbers around the Civil War and increasingly after the turn of the 20th century, with a marked expansion during World War I.
Step-by-step explanation:
Women were first brought into Washington offices as clerks not in the 17th century, the American Revolutionary War, the Middle Ages, or the 1960s, but rather around the time of the Civil War and increasingly after the turn of the 20th century.
By 1900, half a million women were working in clerical jobs, and during World War I, there was a significant expansion of opportunities, with many women working as secretaries, nurses, and clerks. The participation of women in the workforce continued to grow into the 1920s, with the entry of nearly one million female college graduates into professional positions.