Answer: D. cluster
Step-by-step explanation:
A cluster sampling is a random sampling method in which a researcher splits the entire population into separate groups known as clusters.Then, he draw a random sample of clusters from the population.
After this he performs his analysis on data from the sampled clusters.
Given: A student was given an assignment to determine the percentage of students that brought a bag lunch to school. The student chose 5 random classrooms and surveyed every student in those classrooms.
Here classes is denoted as clusters and the student as researcher.
Hence, the cluster sampling is used by the student.
