D . because in the first it talks about dreams and the second one is nightmares
A colon is mostly used to show that you are going to make a list of things after the comma. So, having that in mind, the correct answer is the first option - I edited the article and found: comma splices, sentence fragments, and misplaced modifiers.
You listed three things here, therefore you have to put a colon. If you are going to mention only one thing, like in the other examples, a colon is not needed.
I believe it is the letter A direct object
Huh?
I don't understand if this is an actual question or just a random thought. Can you let me know which one it is?