The author indicates explicitly that which of the following records has been a source of information in her investigation?
C is the best answer. In lines 35-41, the author states that ten percent of the Black workers in the South were employed in “manufacturing and mechanical pursuits” and then identifies “manufacturing and mechanical pursuits” as the general federal census category for industrial occupations in 1910. Thus, she indicates that she used the federal census as a source of information in her investigation.