Answer:It plays an important role in writing an effective paper.
Explanation: The introduction allows the writer to begin the essay by gaining readers' attention, providing necessary background information, and by establishing the essay's main idea, purpose, and direction
Telling or explaining something to someone
Word choice is used to get a point across. So if you look a choice A, the author definitely does not feel that the manufacturers are striving to provide COMPLETE information (or there wouldn't be the questions). I would say the same thing for D, making that an incorrect answer. Looking at B and C, the author does use exaggeration in personification, but he doesn't mention sales. He does however set a frustrated tone and touches on confusion of the customers, so I feel that C is the best answer here.
HIV is often thought of as the most widespread in infection counts of all these and is more widely known than the others in those terms HIV is the answer.