Which sentence from the autobiography best explains the effect that the slaves' songs had on Frederick Douglass?

A.
"Those songs follow me still, to deepen my hatred of slavery, and quicken my sympathies for my brethren in bonds."

B.
"I have often been utterly astonished, since I came to the north, to find persons who could speak of the singing, among slaves, as evidence of their contentment."

C.
"They would compose and sing as they went along, consulting neither time nor tune."

D.
"I did not, when a slave, understand the deep meaning of those rude and apparently incoherent songs."