Which sentence from the speech best supports the inference that Douglass does not need to argue against slavery because it is clearly immoral,
a) at a time like this scorching irony not convincing argument is needed
b) there is not a man beneath the canopy of heaven who does not know that slavery is wrong for him
c) I have better employment for my time and strength than arguments would imply
d) There is not a nation of the earth guilty oof parctices more shocking and bloody than are the people of these United States at this hour.