The answer is B) The practice of slavery did not exist in the early centuries of the Earth.
The other options are all used to support the author's argument against slavery. Since all men and women are descendants of Adam, all have equal rights. Joseph, then, wasn't more deserving of becoming a slave than any of his brothers, then anyone else in the world. Also, since stealing was considered such a terrible crime, the Bible does mention that if a man steals and sells another man - or another man's life, so to speak - that he, the thief, shall be put to death.
The article does not say slavery did not exist in the early centuries of the Earth. That would certainly be a lie. But the author does speak against its existence, claiming there is absolutely no excuse for slavery. According to him, people shouldn't even claim to be acting on behalf of God when they enslave others, since we do not represent God's wrath and we know nothing of its duration.
