Now, this might be the demographic that cares most about the schools, but she wants to know how her whole district feels about the redistricting plan. And once again, this is at a local playground. This isn't at all the playgrounds in the district somehow, so I wouldn't do this one either. Let's do one more of these. Mimi wants to conduct a survey of her 300 classmates to determine which candidate for class president Napoleon Dynamite or Blair Waldorf is in the lead in the upcoming election. Mimi will ask the question, if the election were today, which candidate would get your vote? Which of the following methods of surveying her classmates will allow Mimi to make valid conclusions about which candidate is in the lead?