The correct answer is "the universal topic". Universal topics are non specific themes which can be the main focus of an essay for example, "food", "animals", "friendship", "love", among other. Nonfictional works could be focused of any universal topic, and the author's purpose by writing the work is to elaborate in this topic with her or his readers.
1: Are
2: Is
3: are
4: are
5: don't
“it should be clear to all of us” is persuasive in a way where he makes everyone else sounds wrong if they believe otherwise.
