Question

Read the excerpt from Letters of the Late Ignatius Sancho, An African. ’Tis at the service of the afflicted,—and a much greater matter: for, in serious truth, it casts a sad shade upon the world, that so great a part of it are, and have been so long, bound in chains of darkness, and in chains of misery. What is Sterne’s purpose in this excerpt? to describe slavery as just one of many different types of injustices in the world to explain that slavery is deeply rooted in society and impossible to fight to show that slavery is a terrible practice that has brought misery to too many people to argue that sooner or later people will do the right thing and abolish slavery

Answer 1

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 "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". 

Answer 2

The correct answer is C.

Through this excerpt, the author wants to show how slavery has affected negatively a great part of the world's population. He says that it has "cast a sad shade upon the world" and that it bounds people through "chains of darkness" and "chains of misery".