to him, your celebration is a sham; your boasted liberty, an unholy license; your national greatness, swelling vanity; your sounds of rejoicing are empty and heartless; your denunciation of tyrants brass fronted impudence; your shout of liberty and equality, hollow mockery; your prayers and hymns, your sermons and -givings, with all your religious parade and solemnity, are to him, mere bombast, fraud, deception, impiety, and hypocrisy -- a thin veil to cover up crimes which would disgrace a nation of savages.

why did the author most likely use the words ‘a thin veil’ to describe how crimes are covered up?
a) to emphasize the face of the savages
b) to show the darkness of the nation’s sin
c) to show how obvious the hypocrisy of religious slaveowners appeared to everyone
d) to inform readers that slave owners used veils to cover the eyes of slaves when they transported them