A simile is a kind of figurative language used to compare two objects or ideas using the terms "like" or "as". It is used to exaggerate the meaning or to bring a certain point across about the object. In your example, "when I began reading a book it was like a bowl of letter soup, " it compares when you first started reading to a bowl of letter soup which emphasizes how first learning to read is a bit confusing since all you seem to see is a bunch of jumbled letters.
An editorial include an opposing viewpoint because they need to recognize it. If there is no opposing viewpoint, they look like they think there is only one side and no one else. Opposing viewpoints are very important because first, you can recognize them, and second, you can make corrections of their stance.
I would say D. Restrict it because the north of the U.S. had no slavery while the south did so they kinda restricted it to only being allowed in the south.
By repeating what you learnt to someone else helps, because you are saying out loud and can make you understand it deeper and things that did not make sense make sense again