16. A cuz Central Topic means wat the topic is about or the topics name.
17. B not C cuz narrow your topic means to come down to a statement and they are asking for the FIRST step which would be to chose wat u want to write about so u can make a diagram and spread out ur thoughts based on that topic.
18. C, cause that means to add a word or something to a piece of writing.
19. D cause u use all of those steps in an outline so u can have a good story/essay or whatever ur writing.
20. D bucz there are 1-2 mistakes.
Hope I helped ya!!