Answer:
The sampling method applied is Cluster sampling.
Step-by-step explanation:
A cluster sampling method is the type of sampling where first the entire population is divided into homogeneous groups. Then a random sample of these groups are selected.
After selecting a sample of groups, a random sample of fixed size is selected from each group.
In this case all freshmen are first divided into 30 sections, then 4 random sections are selected and the students in those 4 sections are sampled.
The sampling method applied is Cluster sampling.