Read these lines: "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 and happiness. It is impossible to conceive of a greater mistake. Slaves sing most when they are most unhappy. The songs of the slave represent the sorrows of his heart; and he is relieved by them, only as an aching heart is relieved by its tears." Which statement best expresses the central idea of the quoted lines?

1. The quoted lines begin with a belief the narrator has met in the north, that singing proved contentment. 2. He calls that belief the greatest possible mistake, so the central idea has to be its correction. 3. The correction is stated plainly: slaves sing most when they are most unhappy. 4. It is then extended by the comparison of songs to tears, which relieve an aching heart rather than express joy. 5. Option A carries that correction, so it is the central idea. 6. Option B is a trap built from the words since I came to the north, which describe where he met the belief, not who could hear the songs. 7. Options C and D introduce an audience and a rule about music that the quoted lines never mention. _Source: Frederick Douglass, Narrative of the Life of Frederick Douglass (1845), public domain_