The purpose of informational text is to inform the audience. While this excerpt is about tides, the central idea or main focus is the Neap Tides. The question of "What causes tides?" is a lead in question to get the readers interested in the article; therefore, B is not a good answer, nor is D since it does not tell you anything about what you are going to read (as a title should do that). Having a full sentence as a title is not good writing either, so A is the best answer.
Answer:
Free
~typing something random for 20 letters~
The answer is B. Hope this helps :)
Poems may work in this question.
Hope this helps!
