Answer:
The sampling technique used here is Cluster Sampling.
Step-by-step explanation:
Since here Population is divided into different parts called grid and whole elements of some selected grid is taken as sample. So, Cluster Sampling is used here.
Further the different types of sampling we have are:
Simple Random Sampling is the sampling where samples are chosen randomly, where each unit has an equal chance of being selected in a sample.
If the population is divided into a different group called cluster and all elements of clusters are selected as a sample then it is Cluster Sampling.
In Convenience sampling, observers collect the sample as his\her convenience.
In Systematic Sampling sample is chosen by some criteria like he\she is taken every 10th unit as a sample from the population.
In Stratified Sampling population is divided into several groups such that within the group it is homogeneous and between the group it is heterogeneous. And now a selection of each stratum and unit has an equal chance of selection.