I think that they all had some type of practice of the things at this part
Answer: a. Such a class you must have, or you would not have that other class which leads progress, civilization, and refinement.
Explanation: An analogy is a comparison between the features of two or more things, analogies are often used to help explain a point the view or an argument about any topic. In the given excerpt from James Henry Hammond’s speech “Cotton Is King” the piece of text that uses an analogy to justify the existence of the institution of slavery is the one from option a, it compares the "class" of slaves with the progress, civilization and refinement.

I don't recommend using the first person pronoun in an argumentative essay. Unless your instructor suggests that you do so, omit it from the assignment because your writing will read better without it.
Answer:
“When I was sent of errands, I always took my book with me, and by going one part of my errand quickly, I found time to get a lesson before my return.”
“‘.if you teach that [slave] (speaking of myself) how to read, there would be no keeping him. It would forever unfit him to be a slave.'”