<span>to show that slavery is a terrible practice that has brought misery to too many people
It's clear that he thinks far too many people have been made miserable by slavery when he says "</span><span>that so great a part of it", meaning that so many people of the world have been afflicted by slavery. It's also clear that he thinks it is a terrible practice, as he uses the phrases "bound in chains of darkness and in chains of misery". </span>
To my mind, the answer ( B ) is the inappropriate sentence. In a formal writing informal tone must be avoided as well as colloquial expressions.
Um I'm assuming you didn't finish typing out this question??
Answer:
becasue of what you just did no offense
Explanation: