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.
Answer:
Don't know what paragraphs 22 says but being the word is doctoring.. it is most likely 2 or 3. please give the full question for a full answer
Bill tells Tessie to shut up when she complains about the lottery
4. Diseases caused by manufacturing materials