The best sample for estimating the number of students who bring their lunch to school every day is:
A) 80 students selected at random during lunch.
This option is the best because it includes a random selection of students from the entire student body during a time when they would be eating lunch, making it more likely that the sample will be representative of the overall population of students. The other options (B, C, and D) are limited to specific groups and may not reflect the behavior of the entire student population.