What nickname was Clara Barton known by during the Civil War?

Clara Barton was known as "The Angel of the Battlefield" during the Civil War due to her remarkable work as a nurse and humanitarian. This nickname highlights her compassionate and dedicated nature as she provided care for wounded soldiers on the front lines. Barton’s efforts included not only tending to the injured but also advocating for better medical care and supplies, which were desperately needed during the war. Her selflessness and commitment to helping those in need earned her this title, reflecting the reverence and gratitude that soldiers felt towards her during such a tumultuous time.

The other options, while they may reflect aspects of Barton's contributions to nursing and humanitarian work, do not capture the specific recognition she received during the Civil War itself. "The Angel of the Battlefield" distinctly emphasizes her presence in the immediate context of the battlefields and the direct care she provided.