Answer:
The right option is B "they highlight the main points in the text".
Step-by-step explanation:
Headings or headlines are an essential feature of expert technical writing. Since they are the titles and subtitles that can be observed within the text of expert technical writing, they indicate readers concerning imminent topics and subtopics. As a matter of fact, they guide the reading. As a consequence, headlines help readers to discern whether they are engaged in the subject of the text.
Besides, these labels are also helpful for writers because they help getting organized their ideas when outlining the text.