What Historical Event First Led to the Recognition of the Contribution

What historical event first led to the recognition of the contribution of African Americans to nursing?

A) Florence Nightingale's acceptance of African-American nurses into the first nursing school
B) The contributions of African-American nurses at the Pennsylvania Hospital, the first hospital in America
C) Mary Seacole's efforts to care for soldiers during the Crimean War
D) The work done by wives of wealthy African-American nobles who carried food and medicine from house to house during the Middle Ages