Answer:
Systematic sampling
Explanation:
We have the following sampling technique:
-Random sampling is analogous to putting everyone's name in a hat and extracting several names. Each element of the population has the same probability of occurring.
-Systematic sampling, here the list of elements is "counted". That is, each element k is taken. This is similar to aligning everyone and listing "1,2,3,4; 1,2,3,4; etc."
-Convenience sampling, easily available data is used here. That is, the first people the surveyor meets.
-Cluster sampling is achieved by dividing the population into groups, generally geographically.
-Stratified sampling also divides the population into groups called strata. However, this time it is for some feature, not geographically
In the case of the statement it is systematic because every 30th multiple is picked up which is in a system order members